Utterly Mad

It's also one of the more NSFW things I've seen, the game is pretty okay too.

Spoiler: important plot elements in beserk (hover to show)

Just to highlight some of the nastyness in Beserk, from the little I know about it, although it apparently gets worse than this
Dude who used to be friends with everyone gets tortured, like real fuckin bad.
Makes a pact with evil demon gods
Demons turn up, start killing, eating and raping everyone
Dude turns into a sort of Demi-God
Dude rapes one of his old friends, she basically loses her fucking mind and becomes totally out of it, basically a vegetable
Main character is basically the hulk, has giant sword, gets hunted by demons while dragging vegetable girl around with him because he's in love with her.