Painkiller: Overdose

This was originally designed as an addon, but they were embraced and funded by the developers to turn it into a full game.  Belial -  half-demon/half-angel and the powers of both was too powerful to be let free, so he had his wings torn and was cast into a pit of purgatory.

The story takes place immediately after the ending of Painkiller Black - after Daniel defeats Azrael, the bonds holding Belial weaken, and he begins his 16 level climb through purgatory to exact his revenge.  Each level has a theme that is a purgatory equivalent; a (n evil) farm, a (n evil) fun park, a (n evil) viking shore, etc.

Even though Belial was "so powerful he must be imprisoned" - you are restricted to weapons with ammo, there is no additional demonicishness power that he can use and he plays very much like a normal mercenary.  The only way you know he's really a demon is by his saying "delicious!" as you pick up souls or his bit of flavor at the beginning of a level - "Smells like burning flesh - man, I'm hungry!"

This game really is a mod pack with a few cinematics attached to it.  It's harder than the first in that some levels you seem a little unbalanced or under-funded in ammo, but I think this works out well, as it makes you aim instead of spray - or use the right weapon against the right mob.  Recommended?  If you enjoyed Painkiller Black and want just a little bit more.