This is a very neat game for me personally because I was strongly considering a similar type of gameplay for my own project this year! There's a lot of stuff that you've done with the concept that I've never even considered. Real-time 2D pathfinding is one of the things that scared me off from attempting it, but it seems to be working perfectly fine in your implementation!
I really like the visuals for various ghost power effects. The characters and environment are also looking good. The fetch and deliver mechanics are cool, there's a lot you can do with those! There are some really exciting ideas in this prototype, and I hope that you're planning on expanding it into something bigger!