Fun game with a fun gimmick!
The wildcard implementation was cool, though I agree with @Urwinc that it would have been cool to have each enemy/playable character be more distinct. I was really looking forward to being able to go through walls as a ghost and was disappointed when I couldn't.
It also seemed like the enemies were getting stuck on corners a lot. It seems like they might just being trying to take a straight line path to the player's coordinates instead of actual navigating around the level geometry. Godot has built in Nodes for setting up a NavMesh that make it really easy to set up, I would recommend checking that out for your next project
Over all fun theming, I especially liked how the audio changed for each level. Some of the weapons were fun tie-ins to the creature lore as well (garlic for vampires, salt for ghost).
Nice work!