[Marcus10110]

> Do not move off the left or right side

Turns out if you do this, then hold the up key, it would appear that you avoid collision detection. Also, it appears your X position is preserved between levels, allowing you to hold the up arrow to rapidly advance levels.

[damiankennedy]

For extra fun, remove the "uncompressed" onkeydown added at the end, then you can hold down the spacebar to do big jumps.