This is great. The gears fit together so satisfyingly and it is a really fun idea. The artwork is interesting and cohesive (the water looks amazing). I think this is my highest rated game so far.
I did come across something that you might want to think about - several times, when I was trying to drag the screen, I accidentally clicked on a gear and moved it out of position, causing the machine to stop working. I thought, I wish I could do something, like lock the gears down or use a different button for the screen and the gears, so this wouldn't happen. At the current pace of the enemies, it didn't really cause much trouble, but if maybe at a higher level, the enemies are faster/more powerful, accidentally stopping the machine might be very detrimental.
Good luck with this one! I think it has high potential.