I really liked the atmosphere of this entry. The character art and major prop pieces are gorgeous. The little friend is a fun premise and the mechanic works pretty well.
I'll admit to not having the patience to finish. I fell back down to where you get the friend by accident, and it seemed like the only way to get back to where I needed/wanted to go, was to do a giant loop again. You have other places where you've set up shortcuts that open up after you've passed an area the first time. It would be nice to have one here, too.
My other main gripe is the movement of the character. Smaller platforms can be very hard to land, especially from below. After experimenting it some, I realized it's because the jump stops moving left and right as soon as you let off the movement key, but the walk has momentum. The inconsistensy leads to holding the left button (for instance) while jumping to get up to the platform, but because the platform is close to peak jump height, as soon as the engine detects that the character is grounded, if I let off, the character will slide right off the other side of the platform. If I tried to be gentle about the jump velocity, as soon as I let off, the character stops moving in the air and falls straight down, missing the platform from the front. I found the best way to deal with it was to always hit jump again when landing on small platforms so that I could have the character jump straight up to stop the momentum. It made the rest of the platforming palatable, but was definitely awkward.
Lastly, an aesthetic note: the platform/level art lacks the detail of the character stuff making the overall presentation inconsistent. The levels seem really bare, but the characters are very detailed.
Overall, there's a lot of good stuff in this build, and the premise, atmosphere, and mechanics are compelling enough that I still may come back to it to see it through to the "end" after I've had a break from the 40-some-odd metroidvanias I've played in the last few days ; )