I really liked the art and sounds!
I wish you added some checkpoints, since most of the jumps require you to jump from the very edge it can be really easy to miss, especially when there are so many in a row, and getting sent allll the way back felt a bit frustrating.
I really liked the level with the guards that you have to pop in and out! That to me was the best use of your games mechanics!
Something to consider adding is an indication as to where the lava/plasma is in the other world. Many times I got killed through no fault of my own simply because I didn't know where a lava pit was.
Overall I really liked this game! Thank you for making it!