Fun and simple game! Always nice to see how far a few simple rules can go!
I really liked this game, one thing that I think could be a nice change though is being a bit more lenient with the key despawn time xD! For me it was often times a little tight but these are just the things that come with playtesting, the only other thing I really saw any issues with was that it took a bit of time to realize I could only jump again if I was moving down, so for a while it felt like my double jump was randomly not working. But apart from those couple things I enjoyed this game a lot and liked how you stayed true to the style! Nice!