I agree with BuyMyBeard, the blocks need a (non-color) visual cue as to their function. I'm red/green color blind and I kept dying because I couldn't tell which were the red ones (well, not until they killed me).
Ah, I didn't realize there were only three colors. (of course, that doesn't mean they can't have some other difference, but I can understand how that might make you feel like it shouldn't be necessary.)
