Hello! I spent about an hour and a half playing the demo, and found the fruit and the note on the tiny island (I'm from Twitter lol)
There was a camera issue where it did not reset after falling from the area where you hit the rock with the hammer and fall to the small area below it with the cat character. Upon returning to the top part of the level the camera would still be stuck at that specific height instead of being like you were looking down slightly at the level like normal. I'm going to try and stream the demo in the near future and I will see if I can replicate this.
There was also an issue where the airplane power up would still exist even after I had collected it, so I was able to collect it a second time.
I think the biggest thing that stuck out to me though is how easy it is to fall off everything, and when I was trying out the spin dash + jump combo, and with trying the plane and would fall off the level, it became somewhat annoying that I would resume on an earlier portion of the level instead of near the platform I jumped from. This was easier to replicate with the plane in the part of the level mentioned before with the falling bridge part; I could become a plane from that area and float towards the left, fall, and then respawn waaay to the left of that area at the beginning with the rock in the middle of the fence. If falling is going to continue to be a part of this game, I would personally prefer respawning from the area you last jumped from instead of the area to where you are closest to. But I've never really made a game (yet) so I don't know if that could cause some issues. I figure that you've made things the way they are because of a process you have went through so it is difficult for me to feel like it is okay for me to criticize something like this.
One funny thing I came across during that part is the opossum guy would resume walking from A to B and would walk on thin air plus through the gate with the rock in it like it was nothing, lol.
I had no difficulty issues with the spin dash. It's supposed to be a bit hectic. But sometimes when I would jump with it I would make a collision with parts of the level like the corner of a fence which would stop me from advancing, causing me to fall and have to do it over again. That has more to do with the level layout. Getting to the green fruit was very challenging though. Maybe the spin dash could be changed to where you can stop on a dime? I had a hard time stopping sometimes.
The clouds in the last part of the area did not have the shadow underneath the character like on land which made it difficult for me to determine where I was landing as I was moving amongst them. I do not know if this is an error or on purpose. I had been using the shadow to determine difficult jumps.
I will see if I can record all of this again if I have time. Oh and it would be neat to be able to use the sword while using the spin dash, but I understand if this is an upgrade meant for later in the game :) Thank you for allowing us to play it!