Can you describe the character or monsters?

But I already did: a biker with a revolver and a shotgun. With biker goggles, biker bandana, leather vest and I-don't-care-about-shaving type of beard. By the look of him, around his 40ties, with beer belly and a cig in his mouth.
Big clue: he's not the only character you can play as, later you can unlock others.

Oh sorry, I'm a bit tired! :D

That reminds me of Shank, heh! I don't think I've played this game, might've heard of it.

Wasn't it a 2D beat'em up \ platformer?
I can drop another clue if it's too hard.

Yep, it was all over Steam/Humble Bundle at one point. :) I'll wait for the others to ask questions as I haven't played the game, so chances are I won't recognize it as it doesn't ring a bell.

I already know I haven't played it.

I'll ask a technical one: was it released on GOG?

I guess not many people played it... But it's known thanks to some controversy surrounding the game and he dev.
No. Steam-exclusive as far as I know.

Might be Left 4 Dead.

It's not team based.

Can you play as other characters?

Yes, but you need to unlock them using in-game money.

Do you get other weapons aside from the revolver and shotgun?

Each character has his own unique set of two firearms and you can't get any more.

All right, this isn't going well, so I'll have one more clue:
Take their most famous song, replace one letter in the title and you'll have one of the things behind (ongoing) controversy surrounding the game and the dev.