Unused Graphics

Metal Slug 4 has a substantial amount of recycled graphics, both in-game and as leftovers in the graphic tiles, with stuff even from the first game. Heck, it even recycles stuff from a King of Fighters game!

source: 2560 (8x8)

No, seriously, King of Fighters! There's fonts, mugshots, names and other miscellaneous HUD-related graphics stored in the 8x8 tiles. This is just a sample, but it fills up a sizeable portion of the 8x8 tiles.

source: 10691 (Trevor)

Here's them fatties using the Laser. This animation is used in the game, but since there's only two screens in the entire game you're allowed to be fat on, and neither of them have the Laser, it's not seen without using the level select.

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Despite the five new Slugs in the game, you can't complete a level with any of them - despite them going to the trouble of making score tally icons and everything! Except for the bike, You can still see these by warping around with the level select. The Bradley and Melty Honey are coloured like the regular enemy versions instead of the blue and green player variants.

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This "famous photo" is found alongside the graphics of Metal Slug 4's two new item, the Dual Machine Gun and monkey serum.

It's mentioned on both the English and Japanese arcade flyers (thanks to Metal-Geo for first pointing it out years ago!), but doesn't show up anywhere as far as I know. Enomosiki suggests it was intended to unlock the art gallery in the home ports, but why would they advertise that in the arcade?

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Nadia eating a candy bar. Clearly intended to be an idle animation, but Nadia only reuses Eri's bubblegum chewing, and her only idle stances when carrying the Heavy Machine Gun or Dual Machine Gun are shivering and sweating.
This eventually found use in Metal Slug Defense and Attack.

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This animation was originally used for the Ajirabian soldiers bouncing off of awnings in Metal Slug 2; it's been converted for the pirates, but has no use here.

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They even converted the unused lunge attack, and still found no use for it! Credit goes to Divison 六 for these discoveries.

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A hazmat soldier throwing a pipe bomb; they throw the traditional pineapples in-game. This is edited from the unused sprite from the original Metal Slug, and it's not the only one!

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In-game they just borrow the regular soldiers' animations, but these are based off the original burning animations way back in the first Metal Slug!

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Yet another unused sprite of an unused sprite, of a hazmat soldier knifing while laughing. The slight lift of the head and the eyes lighting up are what distinguish it from the knife animation used in-game. Thanks to Division 六 for pointing this out to me!

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The Toschka Dalanue's cannon in Mission 2 has the right-facing angles converted from Metal Slug 2's Big Shiee, even though you can only stand on its left side. Thanks to Division 六.

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The Morden robot from Mission 6 jumping. It only walks along the ground in-game. Thanks to Division 六.

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Divison 六 pointed this out to me: the scientist emptying the bullet from its chamber. They must have been intended to fire multiple shots before reloading, but in-game they always cut (rather choppily) to their animation of fishing ammo from their pocket after every shot.

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These animations for the scientists are not unused, but I get enough emails about them to make it worth a mention.
You encounter them so rarely it's easy to think they can't be set on fire, but in Mission 6 you find them shortly after getting Fire Bombs or the Flame Shot. They reuse the soldier's burning animation until they fall down.

Scientists also have a rarely-seen melee attack that behaves just like their bullets, but if it misses they'll transform themselves into monkeys, that you can pick up for bonus points. They're extremely fussy about using it, though.

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Apparently the boat men in Mission 5 were once prisoners, depicted here tied up and cowering; curiously, there's no animation of them being released from their ropes.
The jumping animation can be glimpsed with a bit of cheating through dipswitches; if you rush to the right side of the screen and destroy the boats as quickly as possible, you can see the boat men leap off the platform...

... but if you use position-warping to keep up with them, you'll see they don't reach the sea and will instead slide uselessly down the banister. Whoops.

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The lumberjack from Mission 2 standing with an axe. There's no animation to transition into sitting or running, so this guy probably would've just been decorative.

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There's two sarcophagi in Mission 4's mummy area, but they're only background decorations; these unused animations suggest they would've been used to spawn mummies and had to be destroyed.

source: 186369 (Marco)

source: 188342 (Trevor)

source: 190681 (Nadia)

source: 192870 (Fio)

The monkey forms all borrow Utan's running animation, but you're only capable of moving at a glacial pace. What a swindle.

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It's Amadeus, the game's big bad! In-game we never see this dude until the final boss, and only from the neck-up peeking out of his various mechs; this implies we would've caught a glimpse of him in a cutscene or observing something before the fight. I would never have known about this without C2000MC/Futaokuu's sprite rip!

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An alternate top for the Sea Satan (Mission 4's boss), complete with varying states of damage... but it looks nothing like the final product. Likely redesigned to serve as a bigger platform when it submerges. Cheers to Divison 六 for this discovery.

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For some reason, Eri's drown animation is located near some of Fio's. It's not even the proper drown animation, but it actually one without the oxygen tank on her back, that is unused.

source: 155944 (Trevor)

source: 166687 (Nadia)

Various death animations for Nadia and Trevor - stabbed (not seen since MS2!), frozen (last seen in MSX!), and skeletonised (only in MS3!). I couldn't get a good palette for Nadia, so I only coloured the ice and left them as they were found in the tile viewer.

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This would've been used for Tarma kicking open the door of the truck he rides in during Mission 1's upper path, but alas, the truck simply appears with the door already open, and him crouching and shooting.

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This is used in the game, but it's mostly obscured by the helicopter and "Mission Complete" or "Mission # Start" text. So there's really little point for it being here.

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The entire rear half of Mission 1's blimp goes unseen in-game, meaning we never see the tail fin in either its pristine or damaged states. Cheers to The Huntress for sharing this.

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Found alongside the graphics for the blimp's armaments is this cannon, repurposed from the the Tetsuyuki (the first boss of Metal Slug) with laser fire lifted from the Keesi II's turbines. Assuming it functioned like the Keesi, it'd be an odd fit for the blimp unless it had a way of moving around. Cheers to The Huntress for the find.

It's not unused graphics or anything, but Enomosiki brought it to my attention with this image, and it's interesting so I thought I'd throw it in here.

Whatever Metal Slug 4 didn't recycle, it frankenstein'd. The sad truth.

Trying to record every leftover graphic in the game's data would be a nightmare, but damned if I didn't try!