I totally agree that ease of use should be a primary concern. In particular, maybe the "Award Targets" could be shown when a level is highlighted in the list, without having to manually press a button to select it? That way, you'd only have to press the button once to start the level, rather than twice.
Also, I'm a big fan of keyboard use, and it surprised me that ESC didn't pause the game. Generally, you tend to see ESC being used to backtrack through menus, and ENTER being used to select (in this case, start whichever level is highlighted).
Also, a technical issue:
When I choose 1280 as the resolution, the whole game darkens, like it lost brightness. I can't determine if this is a setting on my machine somewhere, but I don't think it is. This happened whether it was fullscreen or not. Is it 1280x800 or 1280x960? It'd be helpful to see the whole resolution, rather than just the X value.
All in all, really fun game, and clever puzzles.