Impressive, very nice.
A bit of a nitpick I've got is that the pathfinding for the smaller creatures is rather wacky if you stand near the vending machine.
The tiny grubs get stuck on the top level ledges, and the flying bug also frequently gets stuck on the underside of ledges and behind the green spewer thing, leading to the larger bipeds to get stuck behind it.
Buying the flamethrower and then attempting to buy more ammo, the price ends up with a very large number, and you can't actually buy flamethrower ammo by the looks of it.
Gun sounds are very quiet. It feels like you're shooting an airsoft gun.
Aside from all that, I am very interested in how this project goes.