WASD to move
Mouse to aim, LMB to fire
E to pick up guns

Swapping guns gets you 5 points and stops bad guys from spawning for the rest of the stage.

Dev notes

Made the core loop in zero hours, then took a couple minutes to add a couple more guns and stage variants. 

The .exe download runs at a fixed timescale of 60 steps per second, the browser version is kinda wacky timescale-wise. The pathfinding in the browser version is also kinda broken. That's game maker for ya, can't be assed to fix any of this. 

There's also a PS Vita VPK file available for download, if you're into that sort of thing. Hastily thrown together, don't expect it to function flawlessly.