Really good game. It was fun to find out some speedrun techniques, even though I always got D or worse.
The aesthetic is really well done but I feel the font was a bit too much. It's fine in general but the objective and dialogue lines were hard to parse quickly.
Apart from the lag, the two issues I encountered were that sometimes running up slopes halts movement and that the keys were not interactable from certain angles.
The sever heart ability is really interesting as a concept but it serves only 2 purpose in the game. Maybe there could be more mechanics that use it or have a more central role in the narrative. Also the heartbeat as a stamina indicator is a cool idea but its volume was too low to good at that.