This is a great little platformer, and has the potential of being a cult hit, sort of like Shovel Knight style. I love the concept. The gameplay mechanic potential etc. The movement needs a bit of fine tuning and work, but it's on the right track. You definitely need to actually implement 'lives' so that you don't have to restart from the very beginning after one failure? Unless this was intentional so that the player masters the entire level and finishes it unhurt...?
Also, the messages when you get the new abilities are confusing, because you can see them BEFORE you get the chest haha! Maybe a 'dramatic pause', a tada sound when you get the ability would have helped to notice it immediately. Unfortunately I didn't find it useful enough to drop my coins, but I can tell this spin is a great idea, I've always told people in this jam with similar ideas, that maybe you just slow the player down, so make it an interesting trade-off decision for the player: you want more coins, fine, but you're slow, otherwise be fast and go away with nothing.
Sadly as others noted, no music in this game, but I don't fault the team. I had no time to put any music in my game either, but at least I had some SFX.. would have liked to see (or rather hear!) some audio in this one.