Perfect for its intent
Given its intended platform, this game has it just right. It's fast, mentally stimulating, and easy to drop in and out. As a Flash game, it's difficult, but I can totally see it rocking a multi-touch interface.
I wouldn't mind seeing just a bit more color differentiation to make responses even more lightning-paced; your palette tends to be rather muted, and I think bold colors could give the game a slightly improved aesthetic (unless you were going for something more muted.) I'll confess I only got through three levels, but I wouldn't mind seeing purples, blacks, or whites that pop right out.
Gameplay is solid, and while I don't know that I'd call it a "puzzle" per se, it's certainly entertaining. I see lots of potential. The 7 is only because it lacks much depth, but given your intent that's not a big deal. Consider an Android port for the rest of us, too!