Too easy to cheat (by accident too!)
I like the idea, but there's no penalty for hitting the wrong button. Thus you can just hold down a button. If that weren't bad enough, holding down the button makes the box count each instant it's at the bottom of the screen (usually 5 or 10 box points per box). If you are honest, you could accidentally hold the key down too long as well and get quite a few extra points you don't deserve.
Make another version with a missed box penalty.
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