Which Metal Slug game are these sprites from?

I've played all the Metal Slug games over the years but I'm having a hard time remembering which one these images are from. I've tried image searching, but there are literally 6 billion Metal Slug images online to sift through.

And for what's going on: Cartoonsmart.com is a cool site that sells video tutorials for Flash and iOS, etc and sometimes they partner with people and sell someone else's tutorials on their site. Today I got an email about this new starter kit they were selling for iOS. I didn't see the sprites until part of the video shows the full sprite sheet and I was like wait... that's Metal Slug. I figured whoever made the starter kit just threw those in for teaching purposes. They still shouldn't be selling them included in a starter kit though... but then I decided to look up Commander Cool on the App store and sure enough the game features a lot of sprites lifted directly from Metal Slug series.

You can see the sprites I'm trying to figure out here:

http://itunes.apple.com/us/app/commander-cool-lite/id505849657?mt=8

I wanted to know what specific game so I can email the Cartoon Smart guy and let him know he might want to not do business with these guys as he is in effect re-selling copyright infringing material.

The guys that made the game over at http://commander-cool.com/ios-2d-platformer-starter-kit.html have this to say on their Starter Kit page

Disclaimer
You are free to use all source code contained in the ‘CommanderCool‘ folder for your own private and/or commercial use, however, artwork, music tracks, fonts and sound effects included in this package will remain the copyright Janzen & Strauß.

At least one of the people that rated the game on the App Store called them out.

I don't recognize that from any one Metal Slug game but he does look like he animates exactly like Marco, and the sprite shares a lot in common with him. Maybe they swapped some pixels around.

Looks like they altered him a bit, but it looks like Marco. I wouldn't worry about knowing the specific game when it's as easy as showing him Metal Slug. If he cannot make the comparisons, do it for him.

That's pretty much almost every Metal Slug game since it's Marco.

Looks like the sprite edits we used to do in MUGEN. Those definitely started as Marco but who knows from what game. I dont think it should matter what game anyways, just say they are from the Metal Slug series.

Yeah, that's just a pretty standard Marco recolor. Considering he basically looks the same in every game (including that very specific victory pose in the app icon), take your pick on any Metal Slug from 2 through XX?

Even if it's free, they mention they pretend that the sprite is their own but that is obvious copyright of SNK Playmore.

I don't think the Metal Slug games have ever gone through a full visual redesign.

Thanks everyone. I wasn't sure if it was some character I didn't play much or if it was Marco. Every frame of animation is dead on though. I asked them on twitter why they're using metal slug sprites and claiming copyright and they tell me they aren't claiming it but that they had someone else make the artwork and that person has the copyright. I can totally understand using some game assets as filler just to test things. I do that in Unity all the time. It's just insane to me that people would actually lift assets like this from a pretty well known series and use them in their game.