Devilishly awesome! I absolutely loved how responsive the gameplay felt and it's quite refreshing to see a first person shooter among all the other games in the jam. The flying skulls were a good enemy, though they were really easy to dodge and I found myself almost exclusively attacking the eye - I think having some different types of skulls that could do different things (or even The Eye itself) (for example shoot projectiles) could up the difficulty in a good way.
The art is crazy good and the music is perfect for this game, though a bit too loud compared to other sound effects in the game. I'm curious (you haven't written anything about it), did you make the music yourself?