Extreme hardcore nightmare

Replace zombies with Mr. X, William Birkin (G1) and Super Tyrant.
Replace G-Adults (G3) with William Birkin

Ultimate Survival Nightmare

Replace Zombies with Mr. X, William Birkin (G1) and Super Tyrant
Replace G-Adults and William Birkin (G3)

Fluffy Mod Manager is required for installation!

Let your skills test whether you can survive the ultimate survival horror

Known issues
Birkin G1 is immortal, may continue to chase and push you the best way to leave him!