Doom 3, Quake 4, or other cool pc mods recommendations

[ACHlLLES]

Zombie Slayer, good looking game looks like the creator put a fair amount of effort into creating it but the game is quite short but pretty bad ass while it lasts.

http://www.moddb.com/mods/zombie-slayer

[Kivian]

There's a kickass predator mod for Oblivion