This is a GZDoom only project i'm working on. I'm serious this time! Unless ST has model and 3d floor support, this isn't getting anywhere other than GZdoom.
Zombie outbreak is about one thing. Survival! Hopefully these screenshots should give you an idea of what's to come:

What a creepy looking house! Not my idea of a vacation!

Looks like nobodys home...

AAAAAARGHH!! ZOMBIES!!!!

They're breaking in!

Use the crate to block them out!

Uh oh... Time to run for it!

Use the valuable rocket to make room!