This is probably one of the top spots for me! I love top down shooters and you did this one really well, it's a cohesive package with everything covered except one thing that I really want for the future, a windows build that I can boot up when I feel like it ;)
On a serious note, something I feel would add to your game is a enemy type that chases you, that you can't run over or maybe trying will kill both of you. It would change how you stragetize your movements and bring a lot more than "aim for the big blob of ammo imps" thing if you get what I mean?
This was my high score: