This is a really fun puzzle game, well done! The mechanics are very interesting and the puzzles are great. The art is also beautiful and the music fits really well!
My only problem is the readability of the game state. The player has to remember the location of the hidden spikes and when they activate, when the mages and slimies are going to shoot and in which direction the skellies are going to move. That's a lot of information to keep track of, which was especially hard for me to do on the last level. The sprites of the mages, slimies and spikes should probably change the turn before they activate, and the location of inactive spikes could be represented with a couple of holes in the ground. The skeletons should turn in the direction that they will be moving next turn. That way, the player has all the information at their disposal. This would prevent a lot of deaths by spikes you did not know where there or by skellies you though were going in the other direction.
I'd really appreciate it if you would have a look at my game as well, and be sure to download the smaller version :D