Took me a while to realise it was turn based and things only happened when I input - neat little puzzle game, simple controls, but it took a while to realise that bones on circles summon demons only when you get to an altar, that the demon is aggressive to the player and that the counter in the bottom right shows his duration - as well as that he takes two turns when you take one! Also, the sprites often got off-center to the tiles, which was a bit confusing. Also, sometimes after restarting a level it restarted a second time after a few seconds randomly.
Still, neat little puzzle game about how to get a demon out of your control to work for you! Presentation is quite neat, and I feel it adheres to the theme very well. Well done!