The possession mechanic was really cool and unique, and I loved the artstyle. The platforming was a bit tough because it was lacking some features like coyote time and jump buffering. For your first game though, it's understandable that you didn't know about these things to make the platforming smoother. Here are some videos on what they are, how they make your platformer feel better to play, and how to implement them. Great first game, and I hope you keep it up!