The graphic changes from the gates are awesome! Graphics in general is pretty nice, quite athmospheric.
You should add a slight window after being ungrounded to allow the player to still jump, sometimes it feels like you should be able to jump, but you cannot. Most platformer games do this. Something like 0,2 seconds after left the ground for example.
Game feels a bit slow and gets pretty boring after a short time. Also it's sometimes hard to see the end of the platforms, and how the map will turn, resulting in missing jumps that feel like they shouldn't miss.
Great job overall, keep up your work!