I like the concept of stopping time to slow yourself, but the game's mechanics could've been executed better. Here are my suggestions:
-Make it so that when the time has stopped, the player can drag and drop the blocks instead of having them hold the SPACE bar. My laptop won't let me use the mouse when a key is held down.
-Reduce the penalty for bumping into blocks probably to 50 points. 500 is way too harsh.
-If you wish, you can add power-ups so that players can use them to destroy blocks while they are moving.