Hey, just tried this out and it's really fun! There's some really good puzzles here. The three floor one with the scientist was awesome! There's so many ways you can mess it up and it felt great once I did everything right.
I definitely agree with Seiseki that there needs to be more of a tutorial, though. I just had to trial and error my way to figuring out how jumping worked, that there was a range I could possess things, what each thing can do, etc.. I'd ramp things up a lot slower, like just have the first level only involve moving, jumping, and climbing. Then introduce a more simple possession puzzle with no possible failstate. Then a puzzle where you can fail, and inform the player they can restart.
I also had a game breaking error on the first level with the possessable hanging platforms:
ERROR in
action number 1
of Create Event
for object objEpossessout:
Error in code at line 40:
bitanim[i]=-16+(((bity[i]-objRC1.y)/(y-objRC1.y))*16);
at position 47: Division by 0.
I'll let you know once I play through the rest. Fortunately, I discovered the skip level key so I won't have to restart completely.
Edit: All done! There were only a couple levels left.
The outdoor levels are really fun, with all the awesome new things you can possess. The spider is fun to control, though there was one spot that felt kinda weird. In the last level where you have to lower yourself and then grab on a wall, it felt like I should be able to press left or right to grab on.
The crash appears to happen when the player is on the center of the moving platform and unpossesses it. Also, I had another platform related bug. It got killed by a saw when I was on it, but I survived. The collision box for the platform was still there and I could climb on it, though.