Metal Slug Wiki

This is a documentation about a Japanese Metal Slug Advance prototype found and dumped by endrift on June 4, 2020.

General Differences


MSAdv Proto Screen.png
MSAdv Final Screen.png
  • The entire prototype has a darker color palette than the final.
  • Walter and Tyra's health gauge is orange instead of green. The gauge resets when entering a new section, but this is purely visual. Getting damaged fixes the gauge.
  • The Slug's gauge is correctly colored but buggy as it doesn't deplete when damaged. The prototype does track the Slug's health.
  • The Ammo and Bomb count is colored grey instead of orange. The infinity symbol is correctly colored.
  • The cards have a different sprite.
  • Pausing the game does not dim the screen. Choosing to return to camp unpauses the game.

Title Screen

Final JP
Final US
MSAdv Proto Title.png
MSAdv Final JP Title.png
MSAdv Final US Title.png

The title screen lacks the katakana text on top and the trademark symbol next to "Metal Slug". It also doesn't loop back to the developer screens if the player fails to press start after a few seconds.

File Select

Final JP
Final US
MSAdv Proto File Select.png
MSAdv Final JP File Select.png
MSAdv Final US File Select.png
  • The prototype has two save files with different progress with Walter's file in particular having cleared six missions. All files function the same, and the player can open one of the saved files and select the opposite character.
  • There is no difficulty select when starting a new game.
  • There is no auto-fire option, and thus, no auto-fire.
  • The introduction scene of the player character and the P.F. cadets arriving on the island is not present.

Soldier Select

MSAdv Proto Walter.png
MSAdv Proto Tyra.png
MSAdv Final Walter.png
MSAdv Final Tyra.png

Aside from the darker palette, Tyra's greyscale mugshot has more detail in the prototype.

Base Camp

Final JP
Final US
MSAdv Proto Menu.png
MSAdv Final JP Menu.png
MSAdv Final US Menu.png
  • Instances where the right side dims in the final is not present in the prototype.
  • All cards are listed as if they're collected. Certain cards that affect gameplay don't function.
  • Prisoners are paged by mission number up to Mission 5, so only 25 prisoners are listed. The prototype lacks a prisoner count on the top-right.
  • The save option is meaningless as the prototype resets to original standings after turning the game off.
  • The prototype plays "The Military System" instead of its own unique theme.

Map & Missions

Final JP
Final US
MSAdv Proto Map.png
MSAdv Final JP Map.png
MSAdv Final US Map.png
  • The prototype has all five missions cleared with the Dungeon card found.
  • The text is in English and in a different font, and its surrounding border is discolored.
  • Selecting a mission only shows the image without the "Mission # Start" text and announcer clip.
  • The Dungeon is referred to as "Mission 6" in the prototype. It is also unplayable as Walter and Tyra die after a few screens.
  • Only Mission 1 can be completed. Mission 2 to Mission 5 are unfinished as they lack a functional boss. The player can transition to the next mission by walking to the right of the boss arena. Doing this on Mission 5 loops back to Mission 1.
  • Although clearing Mission 1 sends the player back to Base Camp as in the final release, the prototype thinks the player is still on Mission 1. This causes the menu to break and allows the player to pause there.

Mission Complete

MSAdv Proto Mission Complete.gif
MSAdv Final Mission Complete.gif
  • The sequence starts abruptly when defeating the boss.
  • The prototype writes "Mission Complete" instead of "Mission # Complete!".
  • The final's text mimics the animation from the main series.
  • Walter and Tyra only have one victory animation. In the final, this animation is reserved for Mission 5 while the other missions have them do a different victory pose.

Game Over

MSAdv Proto Game Over.png
MSAdv Final JP Game Over.png

Getting a Game Over in the prototype sends the player back to the title screen. In the final, the player has the option to continue from a checkpoint or return to camp.


  • Walter, Tyra, and the Slugs are immune to certain attacks, but they all lack invincibility frames after their damaged animation ends.
  • The player starts with ammunition count equal to the main series. In the final game, all ammo count is reduced in half, and the player had to collect weapon clip cards to increase ammo count for that specific weapon.
  • Cards, grenades, Fire Bombs, health, and gas cans do not function.
  • Certain enemies have greater resistance or immunity to specific weapons and grenades.
  • Elevators are extremely buggy in the proto. The elevator platform itself has improper collision, but the player can "ride" them by repeatedly jumping on their trail.

Mission 4

MSAdv Proto M401.png
MSAdv Final M401.png
The player starts already on the ground in the prototype instead of parachuting down. The final release places oil barrels above hidden items as a hint.
MSAdv Proto M402.png
MSAdv Final M402.png
The ground has been modified to better tell the player where they can walk on.
MSAdv Proto M403.png
MSAdv Final M403.png
The prototype briefly locks the screen before letting the player pass. This skips the fight against the MH-6S Masknells.
MSAdv Proto M404.png
MSAdv Proto M405.png
MSAdv Proto M406.png
MSAdv Final M404.png
MSAdv Final M405.png
MSAdv Final M406.png
The larger rocky platforms have a repeating flat texture. Their structure are more simpler and have different enemy placements.
MSAdv Proto M407.png
MSAdv Proto M408.png
MSAdv Final M407.png
MSAdv Final M408.png
In the lower route, the right wall was redesigned to make it clearer that the entire left side is solid. The platforms next to it have a different layout.
MSAdv Proto M409.png
MSAdv Proto M410.png
MSAdv Final M409.png
The entire climbing section is slightly wider in the prototype. This is because the lower route leads to a second Slug Mariner section. Like in Mission 3, there is no Slug Mariner and jumping on the water kills the player. In the final release, the exit has been removed, however the layout is still present.
MSAdv Proto M411.png
MSAdv Final M411.png
There's a gap added in the final for some reason.
MSAdv Proto M412.png
MSAdv Proto M413.png
MSAdv Proto M414.png
MSAdv Proto M415.png
MSAdv Final M412.png
MSAdv Final M413.png
MSAdv Final M414.png
MSAdv Final M415.png
The flat girders are widely spaced in the prototype, and the background is positioned differently. The prototype has makeshift bridges over broken gaps while the final has them fixed.
MSAdv Proto M416.png
MSAdv Final M416.png
The elevator platforms and background are different. The floor numbers in the prototype are replaced with arrow signs to help lead the player throughout the section.
MSAdv Proto M417.png
MSAdv Proto M418.png
MSAdv Final M417.png
MSAdv Final M418.png
The far left and right sides are walled off in the final with the background edited, although the player doesn't fall off the sides in the prototype.
MSAdv Proto M419.png
MSAdv Final M419.png
Only The Keesi III's turbines, rocket and soldier hatches, and the turrets are visible. It is stationary, invincible, and cannot hurt the player. Walking to the right side leads to the bridge section of Mission 5.

External Links

Metal Slug Advance
Heroes Walter RyanTyra Elson
NPCs POW (Names) • Rumi AikawaAllen O'Neil Jr.Rebel ArmyRegular Cadets
Enemies Rebel InfantryFanaticsGrenade SoldierBazooka SoldierShielded SoldierBikersRebel RiflemanMortarCannon DiverRocket DiverNativesJaponese InfantryBatCabracan Pod
Enemy Vehicles T-2B Melty HoneyNop-03 SarubiaGirida-OR-ShobuMH-6S MasknellFlying TaraTurretsBalor
Bosses FormorEmain MachaKaladgolgThe Keesi IIICabracan
Mini-Bosses: Allen Jr.
Weapons Heavy Machine GunRocket LauncherShotgunFlame ShotEnemy ChaserIron LizardSuper GrenadeDrop ShotGrenadeFire BombArmor Piercer
Slugs SV-001 (SV-001 Type-R) • Slug FlyerSlug GunnerBlack Hound
Other CardsItemsPA33-21 Boat
Metal Slug Series
Main Series Metal Slug: Super Vehicle-001Metal Slug 2/(X) • Metal Slug 3Metal Slug 4Metal Slug 5Metal Slug 6Metal Slug 7/(XX)
Spin-Offs Metal Slug: 1st MissionMetal Slug: 2nd MissionMetal Slug AdvanceMetal Slug 3DMetal Slug Tactics
Tower Defense Metal Slug DefenseMetal Slug Attack
Mobile Metal Slug MobileMetal Slug Mobile ImpactMetal Slug: Allen's Battle Chronicles (Mobile 3) • Metal Slug Mobile 4 (UMS: Landing) • Metal Slug Soldiers (UMS: Conspiracy) • Metal Slug Fighters (UMS: Fierce Battle) • Metal Slug Warriors (UMS: Triumph) • Metal Slug STGMetal Slug Mars Panic!Metal Slug TacticsMetal Slug M1Metal Slug M2Metal Slug 2013Metal Slug Team MissionMetal Slug: AwakeningMetal Slug: Commander
Pachinkos Metal Slug Type-AMetal Slug SV-001Metal Slug 3
Compilations Metal Slug 4&5Metal Slug AnthologyMetal Slug Complete PCArcade ArchivesNeo Geo Pocket Color Selection
Cancelled / Discontinued Metal Slug GBA PortMetal Slug Zero OnlineMetal Slug TouchMetal Slug RevolutionMetal Slug WarsMetal Slug XX OnlineMetal Slug Infinity
Prototypes Metal Slug Advance
Related Titles
Cameos / Crossovers The King of Fighters '99SNK vs. Capcom: The Match of the MillenniumThe King of Fighters 2000SNK Vs. Capcom: CHAOSNeo-Geo Battle ColiseumThe King of Fighters: Maximum Impact 2SNK Vs. Capcom: Card Fighters ClashSNK Vs. Capcom: Card Fighters DSDays of Memories 2Neo Geo Heroes: Ultimate Shooting!Battle CatsRPG! Sister QuestJetpack JoyrideThe King of Fighters XV
Ikari Warriors Ikari WarriorsVictory RoadIkari III: The RescueIkari: Leona Gekitohen
Irem's D.A.S. Universe Air DuelUndercover CopsIn The HuntGunforce II
Books Metal Slug: The Ultimate HistoryMetal Slug Attack Official Artbook