The game will not allow you to move any faster than one block per 3 frames. Since this game runs at 30 FPS, that allows you to go through a maximum 10 blocks every second! Make sure when you're playing, you have a rhythm of pressing an arrow key every 3-4 frames. Sometimes, if you press the keys too fast, meaning 2 frames after your previous input, you won't move at all. That can throw off your rhythm. Level 30 is a good level to practice this on.