Metal Slug Infinity (also stylized as Metal Slug ∞) is a Tower Defense, Idle RPG developed and published by ekkorr and licensed by SNK for Android and iOS. The game was first released in the Philippines, New Zealand, and Singapore in March 14, 2019 before being released worldwide at April 16, 2019.


MSI Sophia

Metal Slug Infinity is a 2D tower-defense game similar to Metal Slug Defense and Metal Slug Attack. A team of six units comes from a base, runs from left-to-right eliminating enemy units, and ultimately destroys their enemy base from the right. Should enemies bypass the player's frontlines (or vice versa), then the player's units turn around to attack the intruders. It being an Idle RPG, the player has little-to-no control over the units' actions aside from rescuing prisoners and activating frontal attacks. Instead, the player manages the game's various currencies to level up units and Slugs on the fly.

As the player advances through stages, it will become apparent that they're overwhelmed, cannot level up quickly, and slowly stops progressing. Metal Slug Infinity has the Return function, where the player uses the Time Slug to backtrack a number of stages. All units have their level reset, all Gold Mines are reclosed, and the player's gold amount disappears. On the upside, returning boosts the units' stats, increases the gold regeneration rate, and rewards Medals, Gems, and Piece Boxes. The commander's level is increased by the maximum stage reached divided by 100 and rounded down (e.g. stage 2780 is level 27).

The game continues on generating gold and units fighting as the player access menus, goes into battles, and closes the app. The units will march offline until they hit the maximum stage the player reached. The player can hit the lock icon to active Screen Saver mode. This lets the units fight in the background at usual speeds. The player exits out by tapping on the unit five times.

Numeration for gold, power, and level amounts are represented in alphabetical order. For example, 1,000 is written as 1a rather than 1k. The next letter occurs every multiple of a thousand (e.g. 1 million = 1b, 1 billion = 1c, 1 trillion = 1d, etc.). After z is aa, ab, ac and so on.

Upon reaching stage 10,000, aside from enemy Regular Army units now appearing, the player enters what is called a Magnetic Storm. The storm lowers battle speed, teleport chance, and stimpack (speed increase) chance by a percentage per stage. For example, for the first Magnetic Storm, stage 12,000 is 20% while stage 18,000 is 80%.


The game uses a multitude of currencies:

  • MSICurrency Gold Gold's main purpose is to level up Mines and Units in the main battle arena. Gold slowly increases as time advances, but unlike all other currencies, is reset to zero when Returning. Players can increase the rate of income by opening and leveling up Gold Mines with gold. Certain Gold Mine milestones have a substantial rate increase. The player can call the Genie of Lamp to provide the combined amount of all currently leveled Gold Mines.
  • MSICurrency Medal Medals are used to level up the Physical, Flame, and Lightning Type Mastery of all units specific to that type. They can also be used to purchase unit parts in the various shops.
  • MSICurrency Gem Gems are premium currency: some amounts are rewarded through daily missions, achievements, stage milestones, and events, and of course they can be directly purchased using real money. Gems are used to enhance units, promote War Books and Artifacts, merge 5+ star Slugs, and level up commander boosts.
  • Unit Pieces are parts of a unit needed to unlock that specific Unit or be promoted to the next grade (star) after collecting the required amount, highlighted in blue. Left over Unit Pieces are also currencies for enhancing units and War Books. Piece Boxes provide unit pieces of a certain unit at various amounts up to 1,000 pieces.
  • Souls are used to buy Artifact Fragments, Unit Pieces, and EX Slug Boxes at the Unit Soul store. These are obtained by trading excess Unit Pieces of a 10-star unit.
  • MSICurrency Honor Honor Coins are rewarded through the main Player vs. Player battles or by daily missions. These are used to buy Rift Detectors at the PVP store, Artifact Fragment at the Artifact store, and enhancing War Books.
  • MSICurrency Data Chip Data Chips are gathered by defeating stages in the Slug Camp. They're used to level up Slugs. A dismantled Slug returns Chips that've been spent on it.
  • MSICurrency Quark Quark is used to enhance Slugs. Some amount is awarded whenever S / SR / SSR Slugs are dismantled.
  • MSICurrency Infinity Quark Infinity Quark allows direct purchases of SSR Slugs through the Infinity shop. It can only be obtained by dismantling SR or SSR Slugs.
  • MSICurrency Rift Stone Rift Stones are used to purchase or promote Artifacts. They can be obtained by defeating Artifact stages, or through purchase via Gems.
  • And more...

Commander Info

MSI Commander Info
By clicking on the icon at the upper-left, the player can use their medals to level up the elemental type mastery of all Units of that type. Mastery can be leveled up per one, ten, and a hundred levels at once. If the player changes strategies or now prefers specific types, they can reset the level back to one by a fee of 100 Gems.

Gems are used to level up the player's base. Each of the four facilities have members that boost the percentage per grade by 10% (e.g. 4 Stars is 40%). Each member is progressively unlocked from Lv. 6 to Lv. 10.

  • Upgrade Signal Corps: Medals earned are boosted. Its members are Fat Tarma, Dog Mummy, Native, Mummy Fio, and Fat Nadia.
  • Upgrade Transportation Corps: March Speed when offline is boosted. Its members are Mummy, Guerrilla, Gatling Soldier, Chowmein-Conga, and Rebel Rifleman.
  • Forward Base: The starting stage when Returning is increased. It cannot exceed 60% of the previous Return stage. Its members are Zombie Marco, Tarma-C, Gatling Soldier, Fio-2H, and Mars People.
  • Data Chip Research Institute: Data Chip rewards from the Slug Camp are boosted. Its members are Amadeus Soldier, Eri, Donald Morden, Ohumein-Conga (Red), and Special Force.

Other Buffs gives out stats on the Return, Medals earned, Gold Mine boosts, and Offline March Speed and max level. All Buffs is every stat increase through the currently deployed Unit and Slug's abilities, and by the leveled War Books and Artifacts.


MSI Unit

Grades and Promotion

TeamSelect MSI Promo

The player deploys Regular Army units as well as various friendly enemy Units due to the main cast accidentally transporting themselves to a parallel universe after destroying the Time Slug.

Units have various abilities that are unlocked by leveling up or promoting to raise its grade (number of stars). The color of stars represent the number of overall stars. After five yellow stars, level 6 is one purple star. Unit level is increased by collecting a certain number of Unit Pieces or using Soldier Promotion Tickets.

Grade Stars Unit Pieces/Tickets
1 MSIStar 01 10 Pieces
2 MSIStar 01MSIStar 01 30 Pieces
3 MSIStar 01MSIStar 01MSIStar 01 60 Pieces
4 MSIStar 01MSIStar 01MSIStar 01MSIStar 01 100 Pieces
5 MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01 300 Pieces
6 MSIStar 06 700 Pieces
7 MSIStar 06MSIStar 06 1300 Pieces
8 MSIStar 06MSIStar 06MSIStar 06 2100 Pieces or 2 Tickets
9 MSIStar 06MSIStar 06MSIStar 06MSIStar 06 3200 Pieces or 3 Tickets
10 MSIStar 06MSIStar 06MSIStar 06MSIStar 06MSIStar 06 4700 Pieces or 4 Tickets

Unit Pieces are earned by clearing Dungeons, rewards from events and missions, bought through the various Shops, and by purchasing Soldier Boxes at the store. Soldier Promotion Tickets are earned through events or bought at the World Boss store for 3,000 Cores each.

After a unit reaches 10-stars, any excess Unit Pieces can be traded for Souls at a rate of 5:1. Souls can be used at the Soldier Soul store for purchasing Unit Pieces, Artifact Fragments, and EX Slug Boxes.

Abilities and Enhancement

Units have three types of abilities: Level Buff, Possession Bonus, and Skills.

Level Buffs are unit's individual abilities and team boosts that are activated upon reaching level milestones and the unit is part of the active deployment team. The number of skills stops after Lv. 800, and the player can increase the number of ability level milestones by enhancing Units. To enhance a Unit, the player needs Unit Pieces of currently required Units and Gems. An enhanced Unit has a +[number] on the upper right of their icon per enhancement level.

Lv. No. of Units Unit Pieces Each Gems
+1 2 5 300 MSICurrency Gem
+2 2 10 400 MSICurrency Gem
+3 3 20 500 MSICurrency Gem
+4 3 40 700 MSICurrency Gem
+5 4 80 1000 MSICurrency Gem
+6 4 120 1500 MSICurrency Gem
+7 4 200 2000 MSICurrency Gem

Possession Bonus skills activate regardless if they're deployed or not. Even when deployed, some skills only activate when the unit is present on the battlefield. Possession Bonus abilities are usually related outside of the battle such as skipping stages, raising medal rewards, speeding up battle movement, and increasing Type Mastery Enhancement level. Specific units also boost Gold Mine rewards, increase Warp Energy, increase limit sizes, etc.

Skills are various abilities that activated in battle. These are split into three sub-groups:

  • Team Buffs are abilities and boosts that are given to all ally units or those part of a faction. This also includes two battle advancement abilities: Stimpack (increases battle speed) and skipping stages. Each unit has three team buffs that are individually unlocked by reaching a certain grade.
  • Battle Skills are individual skills aside from stat boosts. This grants secondary effects to attacks against enemies such as freezing, poison, stun, slow movement, etc. Some units can also jump over obstacles, charge into the action quickly, or teleport at few spaces from the player's base.
  • Soldier Buffs are individual timed buffs activated when deployed, after certain time passes, or when the unit is under specific HP. Each unit also has at least one complete immunity to an attack effect.

Limit Stage

A deployed Unit and its Slug contribute to the player's Limit Stage. The Limit Stage is the highest stage the player can theoretically reach without hassle. It is counted by the combined total of the Unit's Type Mastery level, its level, its enhanced level, its Slug level, and its Slug enhance level with variance of the War Book's grade. For example: a level 500 +5 Unit deployed with a level 250 +3 Slug while their Type Mastery is at level 1,000 has a Limit Stage of 1758 (500 + 3 + 250 + 3 + 1000).


Units are categorized into three forces:

Faction efficiency is as follows: Regular > Rebel > Another > Regular.

Each unit has their own elemental type: Physical, Flame, and Lightning. The color shield a unit deploys with receives immunity for said type color.

Regular Army

Immune to knockback. These units gain an advantage against the Rebel Army, but are weak against Another Force units.

MSIUnit Marco - H
Marco - H
MSIUnit Zombie Marco
Zombie Marco
MSIUnit Mummy Fio
Mummy Fio
MSIUnit Fat Tarma
Fat Tarma
MSIUnit Hyakutaro
MSIUnit Tarma - C
Tarma - C
MSIUnit Fio - 2H
Fio - 2H
MSIUnit Rumi Aikawa
Rumi Aikawa
MSIUnit Eri
MSIUnit Trevor
MSIUnit Nadia
MSIUnit Fat Nadia
Fat Nadia
MSIUnit Ralf
MSIUnit Clark
MSIUnit Madoka Aikawa
Madoka Aikawa
MSIUnit Eri(On the Shore)
Eri (On the Shore)
MSIUnit Witch Rumi
Witch Rumi
MSIUnit Leona
MSIUnit XA-01 Juggernaut Marco
XA-01 Juggernaut Marco
MSIUnit Cynthia Hartnett
Cynthia Hartnett

Rebel Army

Immune to shock. These units gain an advantage against Another Force units, but are weak against the Regular Army.

MSIUnit Rebel Infantry
Rebel Infantry
MSIUnit Gatling Soldier
Gatling Soldier
MSIUnit Shielded Soldier
Shielded Soldier
MSIUnit Bazooka Soldier
Bazooka Soldier
MSIUnit Rocket Bomb Soldier
Rocket Bomb Soldier
MSIUnit Arabian Soldier
Arabian Soldier
MSIUnit Amadeus Soldier
Amadeus Soldier
MSIUnit Guerrilla
MSIUnit Shielded Guerrilla
Shielded Guerrilla
MSIUnit Bazooka Guerrilla
Bazooka Guerrilla
MSIUnit Special Force (Shielded)
Special Force (Shielded)
MSIUnit Mortar
MSIUnit Rebel Rifleman
Rebel Rifleman
MSIUnit Donald Morden
Donald Morden
MSIUnit F.Bomb Soldier
F. Bomb Soldier
MSIUnit F.Shielded Soldier
F. Shielded Soldier
MSIUnit F.Bazooka Soldier
F. Bazooka Soldier
MSIUnit Mecha Allen
Mecha Allen
MSIUnit Doctor Type- AI
Doctor Type: AI
MSIUnit Sniper
MSIUnit Special Force
Special Force
MSIUnit Commander
MSIUnit Masked Soldier
Masked Soldier
MSIUnit Fio(Double Agent)
Fio (Double Agent)
MSIUnit Werewolf Morden
Werewolf Morden
MSIUnit JadgArmor Doctor - AI
JadgArmor Doctor : AI

Another Force

Immune to stun. These units gain an advantage against Regular Army units, but are weak against the Rebel Army.

MSIUnit Mars People
Mars People
MSIUnit Ring Laser Mecha
Ring Laser Mecha
MSIUnit Invader
MSIUnit Vanguard
MSIUnit Mummy
MSIUnit Zombie(Man)
Zombie (Man)
MSIUnit Zombie(Fattish Man)
Zombie (Fattish Man)
MSIUnit Ohumein-Conga (Red)
Ohumein-Conga (Red)
MSIUnit Native
MSIUnit Tiny UFO Type-A
Tiny UFO Type: A
MSIUnit Winged Invader
Winged Invader
MSIUnit Smasher
MSIUnit Dog Mummy
Dog Mummy
MSIUnit Chowmein-Conga
MSIUnit Nadia(Brainwashed)
Nadia (Brainwashed)
MSIUnit Monoeye
MSIUnit Man Eater
Man Eater
MSIUnit Mars-O'-Lantern
MSIUnit Anubis the Chained
Anubis the Chained
MSIUnit Sasquatch


MSI Slug

Alongside Regular Army vehicles, every unit is able to ride Rebel, Ptolemaic, and Alien machinery regardless on the size of the vehicle or pilot. Units can also ride large mutants such as the Giant Caterpillar. Slugs can be any of the three elemental types. The Unit and Slug's paired Battle Point increases when both are from the same force (e.g. Marco and SV-001; Mortar and Di-Cokka) and same elemental type.

Slugs are leveled up using Data Chips which are earned in the Slug Camp. In the Slug Camp, ten Slugs fight against various units and vehicles as they attempt to destroy the main target. Slugs with a visible pilot are driven by the google-wearing Rebels who fly the R-Shobu.

Unlike the Units, the Slugs do not reset their level upon Returning. Any used Data Chips are returned back to the player for merged and dismantled Slugs. Data Chip rewards are increased by leveling up the Data Chip Research Institute, increasing an Artifact's grade, or by leveling up specific War Books.

Note that assigning a Slug to a Soldier increases that Soldier's stats even when the Slug is not being actively ridden. The Slug's stats act as a multiplier, so it's most effective to pair vehicles with units that have similar strengths. For example, matching a Slug with a high health stat (eg SV-001 Type-R) with a Soldier with a high health stat (eg Fat Tarma) will result in a very tough unit.


Slugs slowly deplete fuel (represented by a green bar) while on the battlefield. Once it loses its health or runs out of fuel, a "TOUCH" icon appears on top. Tapping it allows the unit to send its Slug onto enemy units. Failing to do so simply has the unit safely escape. Frontal attack power is the Unit's attack stat multiplied with the Slug's attack stat.

MSI Slug Bar

Slugs also have the ability to Slug Warp; it's accessed by tapping the icon next to the Gold Mine button to swap between Units and Slugs. Slug Warping skips multiple stages at once shown by the arrow symbol below the respective Slug's icon. The battery symbol represents the amount of energy needed to Slug Warp. The player can only Slug Warp at any stages prior to the max stage traveled and cannot Warp at boss stages.

Rarities and Promotion

Slugs come in three rarities: N, R, SR, and SSR. Normal Slugs are weaker or battered variants of higher rarity Slugs. Slugs can be merged (called "promoting") to increase their grade (stars); merging a 5-star N Slug turns it into a 6-star vehicle that is either an R (most likely), SR (unlikely), or SSR (very unlikely). Slugs can be promoted as long as all three are the same Slug and grade. EX Slugs (either bought, randomly excavated, or randomly promoted from a 4-Star Slug) can be used when merging 5-star Slugs of any type. Combining multiple EX Slugs increases the probability of getting an SR or SSR Slug.

Merging N Slugs gives out a random Slug and elemental type. R, SR, and SSR Slugs do not change into other Slugs, and the type a merged Slug comes out is based on the first Slug selected for promotion. N Slugs can be merged for free; the other Rarities require Gems to merge.

R, SR, and SSR Slugs can be dismantled to receive Quark, which is used to enhance Slugs. SRs and SSRs additionally provide Infinity Quark, which allows direct purchases of SSR Slugs in the Infinity section of the Slug store.

The maximum level of a Slug is determined by its grade, rarity, and enhancement level. Furthermore, grade and rarity determines the maximum enhancement level as well. SSR Slugs are hence *significantly* more valuable than R Slugs, as not only are their base stats higher, their level can be increased much further.

The chances of obtaining R / SR / SSR Slugs from a 5-star N merge varies depending on the number of EX Slugs used:

0 90% 9% 1%
1 70% 27% 3%
2 0% 90% 10%
3 0% 75% 25%

Always merging 3 EX Slugs at a time averages the most SSRs per EX Slug used, even when factoring in SRs dismantled for Infinity Quark. Merging pairs of 2 EX Slugs is not quite as efficient, however, it allows for more Infinity shop purchases - and since such purchases aren't randomised, they can allow for much faster short-term player advancements.

Players interested in long-term advancements should never dismantle SSRs

Aside from Slug Boxes, N Slugs are earned by the Excavation Site. Excavating a site uses every ticket available as long it doesn't exceed the player's Slug limit. Certain units can increase the max ticket account by one once they reach a certain grade.

Excavation Site Slug Grade Soldier Grade per Ticket
General 1-3 MSIStar 01 Arabian Soldier MSIStar 01
MSIStar 01MSIStar 01
MSIStar 01MSIStar 01MSIStar 01
Tiny UFO Type-A MSIStar 01MSIStar 01
MSIStar 01MSIStar 01MSIStar 01
MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01
Zombie (Fattish Man) MSIStar 01MSIStar 01MSIStar 01
MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01
MSIStar 06
Advanced 3-4 MSIStar 01 Smasher MSIStar 01MSIStar 01MSIStar 01
MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01
Trevor MSIStar 01MSIStar 01MSIStar 01MSIStar 01
MSIStar 06
Invader MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01
MSIStar 06MSIStar 06
Expert 4-5 MSIStar 01 Nadia MSIStar 01MSIStar 01MSIStar 01MSIStar 01
Mortar MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01
Marco-H MSIStar 06


These Slugs can be leveled and enhanced beyond any others. Think very carefully before dismantling them - they're seldom awarded, and all types have their strengths.

MSIVehicle SV-001
MSIVehicle Hi-Do
MSIVehicle Tripod
MSIVehicle Invader UFO
Invader UFO
MSIVehicle Big Snail
Big Snail
MSIVehicle Ptolemaic Slug (V)
Ptolemaic Slug (V)
MSIVehicle Slug Mobile
Slug Mobile
MSIVehicle Giant Caterpillar
Giant Caterpillar
MSIVehicle Iron Cab
Iron Cab
MSIVehicle Slug Copter
Slug Copter
MSIVehicle Ostrich
MSIVehicle Rebel Gigant
Rebel Gigant
MSIVehicle Sarubia (PM)
Sarubia (PM)
MSIVehicle Rudolph Donkey
Rudolph Donkey
MSIVehicle Space Tank(X-Mas)
Space Tank (X-Mas)
MSIVehicle Mars Box
Mars Box
MSIVehicle Sasquatch
MSIVehicle Donkey Carriage
Donkey Carriage
MSIVehicle Protogunner
MSIVehicle Mars Mecha
Mars Mecha
MSIVehicle R.R-Shobu
MSIVehicle LV Armor
LV Armor
MSIVehicle Slug Flyer
Slug Flyer
MSIVehicle Shoe
MSIVehicle SV-Camel
MSIVehicle SV-001 Type-R
SV-001 Type-R
MSIVehicle Dai-Manji
MSIVehicle Elephant Slug
Elephant Slug
MSIVehicle Turtle Slug
Turtle Slug
MSIVehicle Metal Duck
Metal Duck
MSIVehicle Seahorse Slug
Seahorse Slug


Stronger vehicles, although ultimately they can be dismantled for Infinity Quark once enough SSRs have been collected.

MSIVehicle Mini U.F.O
Mini U.F.O
MSIVehicle R-Shobu
MSIVehicle Parachuetruck
MSIVehicle Iron Iso
Iron Iso
MSIVehicle Nop-03 Sarubia
Nop-03 Sarubia
MSIVehicle Slugnoid
MSIVehicle Metal Claw
Metal Claw


Low-value vehicles that can be redeemed for some amount of Quark.

MSIVehicle Donkey Slug
Donkey Slug
MSIVehicle Melty Honey
Melty Honey
MSIVehicle Bradley(PM)
Bradley (PM)
MSIVehicle Di-Cokka
MSIVehicle Di-Cokka(PM)
Di-Cokka (PM)
MSIVehicle Girida-O
MSIVehicle Girida-O(PM)
Girida-O (PM)
MSIVehicle MV-280B
MSIVehicle MH-6 s
MH-6 s
MSIVehicle Hover Unit
Hover Unit
MSIVehicle MH-6 s(PM)
MH-6 s (PM)
MSIVehicle Hover Vehicle
Hover Vehicle
MSIVehicle Bradley


Although these are damaged vehicles with very poor battle abilities, they have the potential to evolve to R / SR / SSR forms after repeated merges.

MSIVehicle Battered Di-Cokka
Battered Di-Cokka
MSIVehicle Battered Girida-O
Battered Girida-O
MSIVehicle Battered MH-6 s
Battered MH-6 s
MSIVehicle Battered Bradley
Battered Bradley
MSIVehicle Battered Mini U.F.O
Battered Mini U.F.O
MSIVehicle Weak Donkey
Weak Donkey
MSIVehicle Battered Hover Unit
Battered Hover Unit
MSIVehicle Battered MV-280B
Battered MV-280B
MSIVehicle Battered T-2B Melty Honey
Battered T-2B Melty Honey
MSIVehicle Battered Bradley Ver.P.M
Battered Bradley Ver.P.M

War Books

MSI War Book

War Books are individual enhancements for entire factions and types of Slugs. Each book is leveled up with a specific set of colored books (red, yellow, green, and blue) and/or stones. Players earn more books and stones by fighting in the material's respective Boot Camp.

The Boot Camp has a team of six Units and their Slugs destroying a specific Boss while enemy Units protect it. Stages are unlocked by reaching a specific commander level. Later stages put restrictions such as giving the Boss an elemental type immunity and/or disallow an entire faction from participating.

War Books are purchased through the store. Unlike other stores, all items are eventually sold out.

Below are the requirements to promote a current grade War Book.

Grade Stars Max Level Gems Honor Coins Requirements
1 MSIStar 01 10 100 MSICurrency Gem Purchase at Store
2 MSIStar 01MSIStar 01 20 100 MSICurrency Honor
3 MSIStar 01MSIStar 01MSIStar 01 30 200 MSICurrency Gem
4 MSIStar 01MSIStar 01MSIStar 01MSIStar 01 40 200 MSICurrency Honor
5 MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01 50 300 MSICurrency Gem
6 MSIStar 06 80 300 MSICurrency Gem 22 Books at 5 Star

Commander Lv. 25

7 MSIStar 06MSIStar 06 110 300 MSICurrency Gem 500 MSICurrency Honor 22 Books at 6 Star

Commander Lv. 60

8 MSIStar 06MSIStar 06MSIStar 06 140 300 MSICurrency Gem 600 MSICurrency Honor 22 Books at 7 Star

Commander Lv. 100

9 MSIStar 06MSIStar 06MSIStar 06MSIStar 06 170 400 MSICurrency Gem 600 MSICurrency Honor 22 Books at 8 Star

Commander Lv. 140

10 MSIStar 06MSIStar 06MSIStar 06MSIStar 06MSIStar 06 ? 600 MSICurrency Gem 1,000 MSICurrency Honor 22 Books at 9 Star

Commander Lv. ?

11 MSIStar 11 ? ? ? 22 Books at 10 Star

Commander Lv. ?

12 MSIStar 11MSIStar 11 ? ? ? 22 Books at 11 Star

Commander Lv. 230

13 MSIStar 11MSIStar 11MSIStar 11 ? ? ? ?
14 MSIStar 11MSIStar 11MSIStar 11MSIStar 11 ? ? ? ?
15 MSIStar 11MSIStar 11MSIStar 11MSIStar 11MSIStar 11 ? ? ? ?
16 MSIStar 16 ? ? ? ?

There are 65 books in total, divided over 13 sets. Equipping each book requires 5 points, and the maximum point limit is increased by using Gems and by promoting certain Soldiers. For 4-book and 6-book sets, every two books equipped awards an additional group bonus. For a 3-book set, all of the books must be equipped for the bonus.

Once all 65 books are promoted to 5 stars, the Enhance menu is unlocked. Here, the player uses Enhancement Stones (earned by daily missions, bought at the World Boss shop for 600 Cores, and one is offered for sale each day for 700 Honor Coins), Honor Coins, and required unit pieces to multiply a War Book's bonuses. A fully enhanced set also multiplies all group bonuses. The game enhances a War Book at random, and there's a 60% chance that two War Books will be enhanced by one stone. The game always picks the first book of the lowest grade and the second one at any grade, and it's not possible to enhance a given book twice until all other books have been enhanced at least once.

  • 1st Enhancement: 500 Honor Coins MSICurrency Honor and two Units with 50 Unit Pieces each.
  • 2nd Enhancement: 700 Honor Coins MSICurrency Honor and three Units with 50 Unit Pieces each.
  • 3rd Enhancement: 1000 Honor Coins MSICurrency Honor and four Units with 50 Unit Pieces each.

Enhancement multipliers are as follow:

Stat 1st 2nd 3rd
Attack x50 x2,500 x125,000
Defense x50 x2,500 x125,000
Health x50 x2,500 x125,000
Critical Chance x1.2 x1.5 x2
Critical Damage x50 x2,500 x125,000
Gold Mine Gold Reward x200 x50,000 x20,000,000
Gold Mine Unlock Decrease x500 x250,000 x150,000,000
Gold Mine Level Up Cost Decrease x500 x250,000 x150,000,000
Gold Mine Time Decrease x5 x25 x125
Soldier Level Up Cost Decrease x500 x250,000 ?
Medal Acquisition upon Return x1.3 x1.6 ?
Boot Camp Material Reward x2 x5 ?
Slug Camp Data Chip Reward x2 x3.75 ?
Battle Speed x1.3 x1.6 ?


MSI Artifact

Artifacts are icons representing various units. These icons, when promoted, boosts the stats of the related unit (called Pairsoldier [sic]) by ten levels. Aside from boosting the individual unit's stats on the battlefield or at other modes, leveling up its grade also increases Metal counts, Gold Mine rates, and unit affiliated faction stats.

Artifact fragments are bought by using Honor Coins or Rift Stones. Rift Stones are typically earned through the Battle of Rift, by events, or purchased at the different stores.

Artifact fragments are also earned through the Battle of Rift. Unlike other battles, in these missions, a team of 10 Units are positioned at the center while hordes of enemy units gang up on both sides. These enemies become bigger in size as the goal limit is closer to being met. Battle of Rifts are accessed by using Rift Detectors. Stages are unlocked by reaching its specific Artifact Point which are increased by the combined grade of activated Artifacts.

Artifacts are promoted by collecting a number of Artifact fragments and using Gems and/or Rift Stones.

Grade Star Pieces Gems Rift Stones
1 MSIStar 01 10 200 MSICurrency Gem 2,000 MSICurrency Rift Stone
2 MSIStar 01MSIStar 01 100 4,000 MSICurrency Rift Stone
3 MSIStar 01MSIStar 01MSIStar 01 200 500 MSICurrency Gem 7,000 MSICurrency Rift Stone
4 MSIStar 01MSIStar 01MSIStar 01MSIStar 01 300 12,000 MSICurrency Rift Stone
5 MSIStar 01MSIStar 01MSIStar 01MSIStar 01MSIStar 01 500 800 MSICurrency Gem 18,000 MSICurrency Rift Stone
6 MSIStar 06 1,000 24,000 MSICurrency Rift Stone
7 MSIStar 06MSIStar 06 ? ? ?
8 MSIStar 06MSIStar 06MSIStar 06 1,600 1200 MSICurrency Gem 30,000 MSICurrency Rift Stone
9 MSIStar 06MSIStar 06MSIStar 06MSIStar 06 ? ? ?
10 MSIStar 06MSIStar 06MSIStar 06MSIStar 06MSIStar 06 ? ? ?


MSI Battle


The player fights against an opponent's battle deck. The unit's level is based on the commander level. The battle ends when a player's base is destroyed or all units in a deck are defeated. Gems and Honor Coins are rewarded daily and weekly through rankings. Each battle costs a PVP ticket.


The player attempts to reach a high score by defeating enemies. Unlike other modes, the singular unit is controlled by pressing buttons to attack and dodge, and moving the virtual joystick to move and aim. Unit and Slug Pieces are given per number of attempts. Each attempt is one credit, and more are earned by collecting Arcade Credits.

There are two arcade cabinets:

  • Destroy the Subway: Marco or Eri attempt to destroy as many Subways as they can under a time limit while various Rebels fight from both sides.
  • Air Strike: The Slug Flyer or Slug Copter fight multiple enemies in the sky.

World Boss

The player base collaborate together to defeat a specific unit with an abundant amount of health. Each time the boss is defeated, everyone is given two rewards. The player can earn more prizes by giving damage to the boss. A fight against the boss ends when all units are defeated or time ends. The player can access three ally skills and one passive skills to deal more damage.

Ally Skills: Accessed once before regenerating again.

  • Defensive Posture: Allies are invincible and have their attacks boosted for a short while.
  • Giant Cogwheel: An enormous cogwheel rolls down the arena and damages the World Boss. Allies have their attacks boosted for a while.
  • Emergency Slug Call: Everyone enters their Slugs. Ally critical chance is boosted for a while.
  • Slug Full Attack: Everyone's Slugs are tossed to the World Boss in which its defenses are reduced for a while.

Passive Skills: Occurs at all times in battle.

  • Heal Over Time: A percentage of health is restored every second for all allies.
  • Quick Reload: Boosts ally's attack speed by a large percentage.
  • Armor Destruction: Decreases the World's Boss' defenses by a large percentage.


  • Metal Slug Infinity's promotional material originally had the working title Metal Slug Frontier, a reference to ekkorr's previous idle RPG game, Endless Frontier.

External Links

Metal Slug Series
Main Series Metal Slug: Super Vehicle-001 | Metal Slug 2/(X) | Metal Slug 3 | Metal Slug 4 | Metal Slug 5 | Metal Slug 6 | Metal Slug 7/(XX)
Spin-Offs Metal Slug: 1st Mission | Metal Slug: 2nd Mission | Metal Slug Advance | Metal Slug 3D
Tower Defense Metal Slug Defense | Metal Slug Attack | Metal Slug Infinity
Mobile Metal Slug Mobile | Metal Slug Mobile Impact | Metal Slug: Allen's Battle Chronicles (Mobile 3) | Metal Slug Mobile 4 (UMS: Login) | Metal Slug Soldiers (UMS: Tank Conspiracy) | Metal Slug Fighters (UMS: Fierce Battle) | Metal Slug Warriors (UMS: Triumph) | Metal Slug STG | Metal Slug Mars Panic! | Metal Slug Tactics | Metal Slug M1 | Metal Slug M2 | Metal Slug 2013 | Metal Slug Team Mission | Metal Slug Code: J
Pachinkos Metal Slug Type-A | Metal Slug SV-001 | Metal Slug 3 (Pachinko)
Compilations Metal Slug 4&5 | Metal Slug Anthology | Metal Slug Complete PC | Arcade Archives
Cancelled / Discontinued Metal Slug Zero | Metal Slug Touch | Metal Slug Revolution | Metal Slug Wars | Metal Slug XX Online
Other SNK Titles
Cameos / Crossovers The King of Fighters '99 | The King of Fighters 2000 | SNK Vs. Capcom: CHAOS | Neo-Geo Battle Coliseum | The King of Fighters: Maximum Impact 2 | SNK Vs. Capcom: Card Fighters Clash | SNK Vs. Capcom: Card Fighters DS | Days of Memories 2 | Neo Geo Heroes: Ultimate Shooting! | Battle Cats | RPG! Sister Quest
Ikari Warriors Ikari Warriors | Victory Road | Ikari III: The Rescue | Ikari: Leona Gekitohen
Irem Games
Irem's D.A.S. Universe

Air Duel | Undercover Cops | In The Hunt | Gunforce II

Books Metal Slug: The Ultimate History | Metal Slug Attack Official Artbook
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