Metal Slug 4 is an arcade run-and-gun and the fourth game in the Metal Slug series. It was the first game developed after the original SNK folded up. The game's copyright information is assigned to Mega Enterprise and Playmore, but much of the actual development was headed by Noise Factory. It was released on March 27, 2002.
This game deals with the Amadeus Syndicate, a paramilitary organization armed with advanced technologies. Marco and Fio are dispatched to the new threat, and are joined by two newcomers, Trevor and Nadia.
It was ported to PlayStation 2 and Xbox.
This work provides examples of:
- Demoted to Extra: Tarma and Eri went from player characters to NPCs in this game, now only appearing as assist characters.
- The End... Or Is It?: The credits screen ends with a sole functioning monitor showing data transmission has been completed.
- "Mission: Impossible" Cable Drop: The Final Mission starts with a section where the player characters descend into the enemy base with their bodies tied to ropes.
- Multiple Endings: It has different endings depending on whether you completed the Final Mission's Escape Sequence. If you did, you and your comrades are invited to a feast and munch delicious dishes. If you didn't, you're sent to the Hospital Epilogue.
- New Work, Recycled Graphics:
- Mission 1 recycles the city graphics from Metal Slug 2's Mission 5.
- Mission 2's later part recycles various levels of Metal Slug (1996): the wild area from the Mission 4, the near-boss area from the Mission 2 in the same game, and then the opening area of the Final Mission.
- Plague Zombie: The zombie virus from Metal Slug 3 once again appears, this time the virus being taken and used by the Amadeus Syndicate to infect an amusement park.
- Sequential Boss: The final boss controls three different mechanical weapons that have to be destroyed sequentially. The first two are robots that take up one side of the screen, while the final one is a Background Boss that shoots lasers and summons robots.
- Sinking Ship Scenario: Mission 5's boss fight starts with the airship boss from Mission 1 showing up and blowing the ship to smithereens.
- Suspiciously Similar Substitute: This game replaces Tarma and Eri with new characters, Trevor and Nadia, but they are really just Head Swaps of the original four, only adding in maybe one or two new animations.
- What Happened to the Mouse?: The final boss is last seen trapped in his own machine in a Collapsing Lair. It's not clear whether he survived or not, and it doesn't help the Amadeus never returned in any other games. His only appearance afterward thus far is canonically-dubious Metal Slug Attack (where his AI inventions are revealed to be bishoujo looking like this
◊, so it's really, really dubious).
