Wow - very challenging game. It took me a bit to get in far enough to appreciate some of the things you did.
I did have a glitch at times after restarting where the L/R arrows didn't respond. It seemed to be stuck in a state from the previous game.
I really liked the variations in the colors and wave formations that you put in as the game progresses - especially the spiral.
The small screen area isn't very forgiving. I might like this better on a larger screen.
Getting my hand from mouse to keys quickly was of paramount importance. Your game may benefit from you capturing the Enter key and letting them start by hitting Enter as well as clicking the button.