Nicely done. Bonuses for placing certain pieces seems poorly designed. Often, the necessary piece is unavailable. Please provide the option to turn off the hint bonuses for relax mode. When I am not in a hurry, I don't need hints and they just take some of the fun away.
Not bad but a bit short and easy.
The monsters that prevent action every few seconds are more irritating than anything else. It just means waiting while it does its little move, again, for a few seconds to try and find the little hotspot that you decided was the only possible solution to the puzzle.
*spoiler*
I think there is something wrong with the puzzle where you spell "machine." It indicates "n" has a value of 4, but that does not work in the puzzle.
While I had the menu up to pause in order to post a comment, the game reverted back to the opening screen and I lost my progress. Not sure if that is the "save glitch," but it is poor design.