I had fun playing it!
List of feedbacks/suggestions:
-The right moving animations moves the sprite slightly to the right, but the left doesn't. Make it consistent. Either none of them move the sprite, or both.
-If you are jumping to a platfrom from below let the character pass, (at least the thin platforms) and then stop the player when falling.
-I kept pressing the W key for jumping, it felt intuitive for me, maybe you can add that?
- As TheRock32 said, add checkpoints.
-Make the background move as the player moves, to make the game feel more 3D like.
-Yea, moving/rotating platforms and other mechanics would make the game better.
Keep it up!