It's unlucky you couldnt get the additional levels in as the idea is really cool, and I think there's loads of additional ways to make it interesting. Power-ups that change the direction you turn could make for some really interesting puzzles. You could have enemies and when you right right click instead of adding a turn marker, it adds an attack command.
Possibly a start-pause button as well, or maybe just have the guy stood still at the start with a start button and a restart button.
I'd like to see more done with this!