I like the concept.
But the execution is lacking.
1. Order of operations. If you're going to multiply, you have to consider order of operations. Either you can alter the equation in the top left to show the "current" number, or you can recalculate the player's number using the order of operations and go from there.
2. Music. Monotonous. Never-ending. Short loop.
3. Controls. They weren't horrible. Moving the character was fine, but throwing something was frustrating. Often times it would land on top of an enemy and not kill him. Also, the juxtaposition of the zoom and fire buttons confused me a couple of times. For some reason, I wanted to jump with z.
4. Notification. Let the player know when they've messed up. Remembering to hit "R" after you've incorrectly moved through a level isn't high priority.
Not bad, overall. I still love the concept. I just wish that the core mechanic of the game was a little more developed. If the mechanic was perfect but the headband didn't wave in the wind, the game would have more value. I guess I'm trying to say that too much time was spent on minor details and not enough time was spent perfecting the core concept.