The really zoomed in camera makes the jumps in this game pretty unfair unfortunately...
It'd be a pretty good idea to show the player how many keys they've collected, and how many there are overall in the level.
Also sound effects aren't 100% required, but they help the game feel less bare, and more reactive to the player's input.
I do think that the platforming is surprisingly solid however, and could act as a great base if you polished the game just a bit more!