Too buggy; couldn't complete.
I was playing level four when the game went haywire. The screen glitched out for a few seconds and then the game was suddenly on a different level. Also, the solutions wouldn't show--all I got was a progress bar that idled forever.
The physics were awfully suspect in this game: Often, the golden gear would be rotating in one direction in the air, but the instant it hit the ground it'd start rotating in the opposite direction.
Forcing the user to make gears mesh perfectly was a bad move. Would it have really been so hard to have the computer to take care of trivial crap like that? Or better yet, how about if the gears are touching, they're just assumed to mesh? Who wants to sit around diddling with pixels?
The dialog box that popped up after every level begging me to register was really annoying, too.