Play The Next Floor flash game

Build up your elevators and man the hallways as you protect your only corridor from the creeps. As the levels progress, enemies get bigger and come in greater numbers.

To fend off these enemies, build elevators and build turrets in them. You don't have to necessarily be on a floor to defend it; if you upgrade your turrets enough, they can work by themselves.

The more you play, the more floors enemies will arrive on. Adding elevators will make your job easier so you don't have to constantly go up and down to prevent the elevator shaft from being destroyed. Be careful; if the baddies do enough damage to an elevator, it will fall, and if you are inside of it it's game over.