Really nice game and concept! The echolocation was nice and it made the game stand out. I think the checkpoints should give you back a heart or two just to help out the player. Also a small bug was a spike killed me and after I respawned it got me again even though it had been released on my last attempt. All things said it was a incredible game and concept, you just needed a bit more time to flesh it out. (Sorry for the long comment)