cute art, fun gameplay, chaos. My kind of game :3
You probably already know that sfx and music would be great here. You could try and get some good soundeffects from jsfxr, its a 8-bit sound generator where i got my sounds from. Also some timed power ups could be fun like a short movement speed or damage buff or an additional poison effect like slow or slipperyness so enemies slide around your poison. A new enemy type could also go along way. maybe a minotaur like boss that charges across the room could be a fun thing to try out.
keep up the good work :D