Windows

Blood II: The Chosen - The Nightmare Levels

Trivia

The three new creatures in this "add-on" (the gremlin, original cultist, and Nightmare endboss) aren't actually new but rather models from the original Blood 2 which were eventually dropped from the game. In fact there's an extra map inside Blood 2 which is basically just a room with the three unused models (they don't do anything, though).