A fun little puzzle platformer from a relatively simply mechanic. I spent maybe more time than I should have playing it just because I was trying to see how low I could get the ghost count. Finally managed 52, although I think there was a lot of luck involved.
I did find the ghost queueing mechanic a little awkward. If you use the arrow keys at the beginning of the level to try to plan ahead, and get one wrong (for example underestimating the height of a jump), you have to clear out everything after that one and redo it all, so I ended up often just adding a ghost or two at time so that I wouldn't waste time adding ghosts I was going to have to re-add later. This obviously wasn't a problem with the early levels, but a couple of the later ones.
And if a "soft goal" is trying to get the lowest ghost count possible, then a level retry might be nice. I found sometimes I thought I would need an extra ghost, and then managed to reach the exit early, and it would have been nice to be able to go back and figure it out without beating the game again.