It's pretty impressive that you did all of this on your own in just 7 days. I would say the movement system needs more refinement, since the way the jump and pads work is not easy to understand, The gravity in the ghost form also has a part in affecting the way the player's velocity works.
However, out of all the jam games I've played for this jam, this specific platformer made me so hooked I poured at least 35 minutes into it, trying to get past stages! It was fun, even it was though frustrating as well xD