An interesting one!
I really like the sound on this one, the different songs depending on wether you are with the ghost or the person. Also the artstyle is nice, though i feel the ghost and the yellow big boxes are a bit too cartoony and clash with everything else, but not that much of a problem. Nice animations overall on everything!
I think the idea is nice and you can do quite a bunch of nice things with it (specially if you were made to hurry in some kind of way, as having to fumble with both characters seems kinda fun). Having to click with the ghost is bothersome, as you have a hand on the arrow keys and one on the spacebar, though this could be aided by using WASD. I'd however just assign another key for it to make it easy to control with just one hand.
Yeah, seems people already told you about the WASD problem so i'll skip it. A few other problems though-
-the white text is hard to read against the white background
-in one run a box glitched and didn't respawn, and i think the level looped
-in another i outright could not summon the ghost again, though i think i tried to carry a box to the next level and it dissapeared aong with it.