Pretty nice - my suggestion would be to rethink the floor tiling as it is hard to see things clearly. We had a similar issue in the early stage of development where we felt like there was a lack of contrast between characters and background, so it took a little tweaking. Figured this would be necessary here as well.

I like these types of games. simple controls but i usually end up just running away in a circle, while the spawning gets out of control. Like the idea of weapon upgrades too. The level design was my only issue with the game. The level does not use patterns and colors in a contrasting enough manner to show clear separation between barriers and the floor. But after getting accustomed to the layout of the level, i ran around in circles trying to make progress and that was fun. 

This could workout well if you matched the power ups with the level of enemies spawning in. so crazy weapons with wider area of damage.

GOOD WORK!

Very cool, looks like we got similar games :)