The icons on the character were a good touch, it helped let me know what maneuvers I had available and a cheeky way of showing your upgrades as a visual change. The music was good but some of the effects (specifically the balls bouncing) were ear piercing (I was on the executable version) The characters controls were a little stiff for me, some moments that required high precision had me getting repeated Game Overs (my hardest hurdles was the emergency lever ascend and the needle thread between the spikes) Luckily the checkpoints are given very generously so repetition wasn't too bad. The upgrades also made backtracking a whole lot easier and is very Metroidvania, when I got to the end and needed to go to the opposite corner of the map to get the missing piece, it was pretty seemless and a good test to see how fast/maneuverable I could be with my full toolset, so good job at the functionality of upgrades! Also bless your soul for an infinite healing mechanic; in a Game Jam, that is a BLESSING!