Metal Slug 4 re-use of graphics

Does anyone know which parts of metal slug 4 are directly ripped off out of other MS games, the part I spotted is the boss of level 3 is MS1's level 5 boss and MS4's level 2 last section is exactly like a bit from metal slug 1 i think...or is it 2?

So crap the way its just ripped off.

Still a fun game though cos its metal slug.

Is this a serious question? I'm surprised you're asking it. It's pretty obvious.

You can use the Search function...there were, um, like 300 threads about this very topic when MS4 came out. Lots of bitching and people with poor taste doing their best to defend the game.