Really good use of illumination - the ping, darkness, and sound effects really gave a sense of tension to the exploring. Sadly my lake of skill at platformers probably stopped me from seeing much of the end game - but I really liked the feel for what I did see. If I had one wish it would be that the echo lightening effect would emit out from the player over time (so that the brightness would start closer to the player and then move outwards away from the player... to help give a feeling of pushing away the darkness).