A good example of simple but clear visuals. l liked how you managed to convey everything necessary using a limited number of colors. Audio is great, especially the sound it made when the clickable area was moving. Loved the pool of blood at game over, slowly expanding and being the only red thing in the entire game. The rythmic mini-game mechanic was also fun.
There's one thing I'd suggest to add: the option to start the ritual without the need to click on the button, but rather with a hotkey like E once the button appeared.