I suggest removing this effect on the upgrade or gun buying screens
Maybe do a brief spazzing out effect when you "boot up" the menu.
The red interlocked circle effect when enemies are hit is a bit too much.
The amount of blood, shells and general mayhem sometimes make it hard to understand what's what and its difficult to understand when an enemy is dead or not so I keep shooting at them.
The camera moves too fast with the mouse.
Overall I really enjoyed the game. The silly premise and the apartment vibe is pretty cool. I also REALLY enjoy the music. Well done. Keep on trucking, dude.