I was enjoying this game a lot until it forced me to become a ghost and remove all the upgrades I had achieved to this point.

I seemingly could only turn back after struggling through an area that would have been difficult at my full strength, let alone in this ghost form. I just got too frustrated with this design decision and haven't come back to it since.

Otherwise though, great game and I do recommend it for the first few hours. You might also just power through the ghost section where I gave up.