I really enjoyed playing, can see the hard work put into it, and I wanted more ^^ I think I did everything? I found elevators for every zone and got the good ending, though a real ending would have been even greater haha. I couldn't beat the shadow mushroom guy but I found and beat the orange goblin.
The mechanics are really well implemented, the double jump was amazing. My guy would throw the boomerang every time I jumped is that intentional? A few times I wanted to jump first and then throw from a height, but automatically throwing meant I couldn't do do that (using gamepad).
I also had the bug in the second goblin home, I thought it might be a secret where you find a torch or something? :')