Don't pass level 18!
The next two levels are even worse!
This game is a load of crap, and I'll tell you why! It has no heart. Each level is either painfully easy, or gut-wrenchingly hard. You either have to press one or two directions go get there, or die a dozen times and memorize the layout of the level, then calculate your timing to the movement of the blocks. And after ALL OF THAT, the ending is just disappointingly easy. My suggestion, stop when it's no longer easy, because it's no longer tolerable.
Also, God help any other poor soul who finds a glitch in their controls, when just for a moment, you can't control him. That's just painful.