Looks great, it has a nice level of polish.
Thank you so much! ^_^
I'm a little confused about the gameplay though.
I hope that when I will release the demo it will be clearer (the game explains the gameplay by some tutorial levels).
Does the player have unlimited gears for each puzzle?
Yep.
What's the red thing to the right of the gear in the bottom right corner?
You have a limited amount of bombs, which you can use to remove "wrong" gears from the level (you can see it at
this point of the gameplay video). It often happens that you place a gear and then realize that it becomes an obstacle.

Also, do you get points on how fast you did it, how few gears you use, or both?
At the moment, I count the number of "active" gears, that is, the number of gears which are moving when you complete a level. Thank you again!
