Metal Slug Wiki
Metal Slug Wiki

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. The game will end service on September 30, 2021 due to termination of license agreement..


MSI Main Screen.PNG

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. 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, Unit Piece Boxes, and Honor Coins. The commander's level is increased to the maximum stage reached divided by 100 and rounded down (e.g. stage 2780 is level 27).

The game continues on generating gold and the units fighting as the player accesses 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 the player now fighting Regular Army units, the player enters what is called a Magnetic Storm. The storm lowers battle speed, teleport chance, and stimpack (speed increase) chance by a percentage. A new Magnetic Storm occurs every 10,000 stages and all storms are applied together.

Magnetic Storm
Effect MS1 MS2 MS3
Battle Speed -0.01% per stage -100% ?
Teleport Chance -0.01% per stage ?
Stimpack Chance -0.01% per stage ?
Attack Range -100
Movement Speed -30


While most action is done automatically, the player can tap on the main battle screen to do some actions. Tapping on enemy units, obstacles, and their base inflicts slight damage to them. Activating frontal attacks are done by tapping on a Slug when it is in the middle of self-destructing. Various items and POWs are found on the battlefield and grants bonuses by tapping on them; upgrading Mummy Fio increases the chance of the item being collected without player input.

  • POW: Gives the player gold and increases battle speed.
  • Treasure Chest: Gives the player gold.
  • Fuel Cell: Increases battle speed.
  • Ammo Box: Boosts active units' attack, defense, and health by 1000% for a minute.


The game uses a multitude of currencies:

  • MSICurrency Gold.png 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.png 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.png 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.
  • MSICurrency Unit Parts.png 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.
  • Mastery Points are used to upgrade a unit's skill tree and boost their stats. These are obtained through the Power Defense mode.
  • MSICurrency Soul.png Souls are used to buy Artifact Fragments, Unit Pieces, and other items at the Exchange Station. These are obtained by trading excess Unit Pieces of a 10-star unit.
  • MSICurrency Honor.png Honor Coins are rewarded through the main Player vs. Player battles, World Boss 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.png 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.png Quark is used to enhance Slugs. Some amount is awarded whenever S / SR / SSR Slugs are dismantled.
  • MSICurrency Infinity Quark.png 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.png Rift Stones are used to purchase or promote Artifacts. They can be obtained by defeating Artifact stages, or through purchase via Gems.
  • MSICurrency Artifact Fragment.png Artifact Fragments are used to unlock and promote Artifacts. They can be obtained by defeating Artifact stages, or through purchase via Rift Stones.
  • MSICurrency Alliance Coin.png Alliance Coins are used to make purchases in the Guild Shop. They can be obtained by completing alliance-related tasks.
  • MSICurrency Core.png Cores are used to make purchases in the World Boss shop. They can be obtained through the related Battle mode.
  • MSICurrency Red Book.pngMSICurrency Blue Book.pngMSICurrency Yellow Book.pngMSICurrency Green Book.pngMSICurrency Rune Stone.png Books are used to upgrade War Books. They're earned through the Boot Camp.
  • MSICurrency Enhancement Stone.png Enhancement Stones are used to make enhancements to War Books. They're occasionally available for purchase through certain shops, or rarely offered as rewards for daily tasks.
  • Tickets are used to access the various submodes (each one having its own ticket), bypass wait times, and obtain Unit Pieces of a player's choice. All of them are given as rewards, although a scant few a bought in stores.
  • And more...


The main bulk of Metal Slug Infinity is in its various submodes used to earn rewards and permanently level up units and Slugs.

  • Commander Info: Level up elemental type masteries and increase rewards and level travel.
  • Units: Earn units, enhance them, equip gear, and unlock specific stats from a skill tree.
  • Slugs: Earn Slugs, level them up, merge lower tier Slugs to get better tier Slugs, and promote them.
  • War Books: Increase faction and Slug stats tenfold.
  • Artifacts: Increase the units' stats and versatility to itself and other factions, submodes, and the main battle mode.
  • Battles: Miscellaneous battles such as PVP, world co-op, and currency collection for specific unit stat modes.
  • Alliance: Cooperative guild mode.
  • Events: Temporary submodes that give out more rewards than usual.

Commander Info

MSI Commander Info.png

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 total grades from all members by a percentage. The first five members are progressively unlocked from Lv. 6 to Lv. 10.; the rest are unlocked upon reaching their appropriate base level.

  • Upgrade Signal Corps: Medals earned are boosted. Boosts by ★ × 10%.
  • Upgrade Transportation Corps: March Speed when offline is boosted. Boosts by ★ × 2%
  • Forward Base: The starting stage when Returning is increased. It cannot exceed 60% of the previous Return stage. Boosts by ★ × 2%.
  • Data Chip Research Institute: Data Chip rewards from the Slug Camp are boosted. Boosts by ★ × 2%.
Bases and Members
Signal Corps Transportation Corps Forward Base Research Institute
Fat Tarma Mummy Zombie Marco Amadeus Soldier
Dog Mummy Guerrilla Tarma-C Eri
Native Shielded Soldier Gatling Soldier Donald Morden
Mummy Fio Chowmain-Conga Fio-2H Ohumein-Conga (Red)
Fat Nadia Rebel Rifleman Mars People Special Force
Allen O'Neil (Lv.22) Commander (Lv.60) Shielded Guerilla (Lv.?)
Tar Man (Lv.26) Sasquatch (Lv.80) Masked Soldier (Lv.41)
Zombie (Woman) (Lv.90) Cynthia Hartnett (Lv.43)
Utan (Lv.45)

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 Battle.png


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. Should a minute pass in battle, everyone's stats are given a full burst.

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 jump, 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.

Currently, there are three 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.
  • Storming the Mothership: A red-clad Bazooka Soldier, Shielded Soldier, or Rebel Infantry (Grenade) fights against Martians and Invaders while various ally Rebels attack and protect for the player.

World Boss

The player base collaborate together to defeat a specific unit with an abundant amount of health. Each time the boss is damaged, everyone is given two rewards: one for personal total damage and the other for collaborate total damage. The player can earn the latter set of prizes by contributing up to seven times per boss. A round 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 waiting for a cooldown.

  • Against Iron Nokana:
    • 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.
  • Against Dai-Manji:
    • Confusion: Enemies barring the boss attack each other for a while.
    • Bombardment Request: Sends an airstrike on screen. Ally attacks are boosted for a while.
    • Concentrated Fire: Ally units target the boss for a while. Ally attack range is boosted for a few seconds.
    • Support Unit: Bazooka Soldiers, Gatling Soldiers, and Lv Armors are deployed for assistance. Allies under electric shock are turned to normal.
  • Against Rebel Gigant:
    • Armor Piercer: All allies' pierce stats are boosted to 100% for a while.
    • Stand-Down: Allies' attack stats are boosted for a bit.
    • 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.
  • Against Jupiter King:
    • Defensive Posture: Allies are invincible and have their attacks boosted for a short while.
    • First Aid: Allies become immune to status ailments for 5 seconds. Electric shock effect is removed.
    • Armor Piercer: Allies' pierce stats are boosted to 100% for a while.
    • Bombardment Request: Sends an airstrike on screen. Ally attacks are boosted 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.

Power Defense

The player earns Mastery Points by leading a team of six units against waves of enemy units. A wave appears on the battlefield after their countdown is up and multiple waves can show up at once. The enemies fought depends on the faction chosen (e.g. the Regular Army fights the Rebel Army). Power Defense only considers the units' grades and enhancement levels. The player nor the enemy use Slugs in this mode.

Unlike other modes, the units are deployed manually, each unit costs a number of summoning points to be deployed, and a cooldown starts before the unit can be deployed again. The summoning point cost and cooldown timer varies on the unit's role, grade, and enhancement level. During a battle, the amount of summoning points increases in intervals and more points are acquired by defeating enemy units.

There are a maximum of 20 stages for the player to traverse from. The higher the stage the more Mastery Points a player can sweepout once they are unable to progress at the moment. The sweepout reward is based on the current highest stage, regardless of faction. A player can only acquire the sweepout reward once per day. The maximum amount of Mastery Points a player can accumulate is based on the number of units in possession x 350 and no more points can be acquired in excess of the max amount. A player can challenge for free twice per day, and a ticket is wasted regardless of the outcome.

Stages 1-13 reward Mastery Points equal to the relative current stage. Stages 14-20 give out higher rewards.

Sweepout Reward
Highest Stage Cleared 1-13 14 15 16 17 18 19 20
Mastery Points 1-13 15 17 19 21 23 26 30



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

External Links

Metal Slug Infinity
Units Regular Army Marco Rossi (Zombie) (XA-01 Juggernaut) | Hyakutaro Ichimonji | Tarma Roving (Fat) | Fio Germi (Mummy) | Rumi Aikawa (Witch) | Eri Kasamoto (On the Shore)| Trevor Spacey | Nadia Cassel (Fat) | Ralf Jones | Clark Still | Madoka Aikawa | Leona Heidern | Utan | Cynthia | Regular Infantry (Santa Camo)
Rebel Army Infantry (Amadeus, Guerilla, PM Special Force) | Gatling Soldier | Shielded Soldier (Guerilla, Rebel Special Force, Future) | Bazooka Soldier (Guerilla, Future) | Rocket Bomb Soldier | Arabian Soldier | Mortar | Rebel Rifleman (Sniper) | Donald Morden (Werewolf) | F. Bomb Soldier | Allen O'Neil (Mecha Allen) | Doctor Type: AI (JadgArmor) | Commander | Masked Soldier | Double Agent Fio | Abul Abbas | Nanook | Arabian Fighter
Another Force Mars People (Mars-O'-Lantern) | Ring Laser Mecha | Invader | Vanguard | Mummy | Zombies (Man, Fattish Man, Woman, Rebel) | Ohumein-Conga | Natives | Tiny-UFO Type: A | Winged Invader | Smasher | Dog Mummy | Chowmein-Conga | Brainwashed Nadia | Monoeye | Man Eater | Anubis the Chained | Sasquatch | Tar Man | Assaultpeng
Slugs SSR SV-001 | Tripod (Mars Box) | Invader UFO | Big Snail | Ptolemaic Slug | Slug Mobile | Giant Caterpillar | Iron Cab | Slug Copter | Ostrich Slug | Rebel Gigant | PM Sarubia | Donkey Carriage (Rudolph Donkey) | Space Tank (X-Mas) | Sasquatch | Protogunner | Regular Iron Nokana | MG Unit | Drill Slug | Pumpkin Head | Redback | Felsteed | Hi-Do | Seahorse Slug | Turtle Slug | Giant Hunter Walker | Bradley Slug | Crab-Tank | R.R-Shobu | Metal Duck | Iron Nokana | Another Iron Nokana | SV-Camel | Slug Flyer SV-001 Type-R | Dai-Manji | LV Armor | Elephant Slug | Mars Mecha | Shoe
SR Mini-UFO | R-Shobu | Parachuetruck | Iron Iso | Nop-03 Sarubia | Slugnoid | Metal Claw
R Donkey Slug | Melty Honey | PM Bradley | Di-Cokka | PM Di-Cokka | Girida-O | PM Girida-O | MV-280B | MH-6s | Hover Unit | PM MH-6s | Hover Vehicle | Bradley
World Bosses Rebel Gigant | Iron Nokana | Jupiter King | Dai-Manji | Monoeye
Submodes Units | Slugs | War Books | Artifacts | Battles | Commander Info | Alliance
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 | Metal Slug Tactics
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: Awakening | Metal Slug: Commander
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 | Neo Geo Pocket Color Selection
Cancelled / Discontinued Metal Slug (GBA) | Metal Slug Zero Online | Metal Slug Touch | Metal Slug Revolution | Metal Slug Wars | Metal Slug XX Online
Prototypes Metal Slug Advance
Related Titles
Cameos / Crossovers The King of Fighters '99 | SNK vs. Capcom: The Match of the Millennium | 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 | Jetpack Joyride | The King of Fighters XV
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