One of my favorites is definitely the final level of Metal Slug 3.
It's bat-poop insane. Talking about it would sound like the blabbering of a deranged old man who belongs in a straitjacket. And watching a video doesn't really have the same effect as playing it yourself, so all I can do is heartily advise you to go out and BUY METAL MOTHERFUCKING SLUG ANTHOLOGY.
Here's how to do spoiler tags, btw. You can see through it if you look at it intently, but if you deliberately look at something you don't want to know, you only have yourself to blame for getting spoiled.







