smooth programming. its was occupying for me simply because i have some radio on itunes playing some trance... it would get boring without something else. no sponsor would want this as of now. its too boring an generic. you should consider all the things the others have said they are all great ideas. looks like you have your own geometry wars going here... except its worse o.o so don't go for the classic enemy and shooting thing. i think the different colored and worthed blocks would be cool and the time limit to get to say 100 would also be fun. uhmmmm and another idea would be to have the blocks change to negative value after it blinks a bit. so its a risk to get higher points...
keep it up but elaborate and be as original as possible.