When trying to move in a direction and jump, it wasn't responding. I had to let go of the arrow button to jump and then press the arrow button to continue moving. I should be able to jump while holding down the directional movement buttons.
Sound Effects/Background Music
The first level was a little brutal. I liked that you had to hit the yellow box as a way to reach the ledge. I didn't have to use the sphere at the end due to the vertical platform allowing me to jump off at the right time to enter the gap. I didn't try other levels after the first.