This game might be problematic for people with epilepsy.
Well, I found this cute, I dunno why
I like your advices
Nice game concept with enemies being visible or invisible, depending on the background color.
The music is catchy, even if I don't want it...but that's the nature of such music.
Controls work fine.
Something is missing though. Maybe it was your intention to keep it as simple as possible,
but how about some power-ups? Nothing fancy, just to spice it up a bit.
Maybe a mini boss as well. A Newgrounds Highscore option would be also nice.
Competition - that's what keeps player playing.
Odd. That's all I have. Not sure who this would appeal to aside from preteens.