Nicely put together. I didn't get too far, I got to the level where stepping off the button made the door close again and I couldn't figure out what to do. Other people seem to have got much further so I'm probably just being stupid but I'd already had to reset the previous level a bunch of times due to getting 1px too close to a spike. I think someone below also mentioned that sometimes its better to go a little more generous with the colliders.
On my first go I did get stuck on the first level, the orange button didn't open the door but now I can't remember if I was already a ghost at that point, I don't think I was.