Neat game, would be interesting if multiple colors arrived at the same time, and there were 3 keys to press. That way there is a bigger chance of making a mistake. 

I would also make the green bar thinner, even to the point of making it a line, so you can see more clearly when the bars are moving across it.

I liked when the bars start disappearing and you have to guess when they'll reach the green bar based on the rithm.