Tested the web version*
I like this topdown doom a lot!
Dunno what your aim is, you have a ton of possibilities. both a hotline miami style or a survivor kind of a game can work with this gameplay; but i must say that your game made me remember the old great twin stick shooters of the early days of iphone. Consider doing closed maps like the one you have now, and the game is to resist for X second to have a medal, unlock stuff, more levels etc
the only thing i really dont like is making your ammo refill by themselves on a long delay. If you wanna keep all the ammo on autorefill, an ammo count on the status bar is a must. so at least you know what weapon is ready to be used again.
Maybe consider a weak weapon with infinite ammo, or with a large magazine that autorefills; but then all the other ammo are just found on bodies like powerups.
I suggest you to check nuclear throne for your wiz ability; you have tp, you can make a ton more, as more chara to use, or skills to equip.
Check also ubermosh, it may spark some new ideas about your game.
I like the style of wiz on coverart. dunno if it's me, but he seems bored
GL