"- MAJOR FIX: The top-right corner of the map had been rendered pretty much inaccessible by accident"
Ahh, not going insane.
One very small nitpick is that I think the jump upgrade could have a more distinct button. I sometimes used it when I actually wanted to use the legs, although I've gotten more used to it by now.
I'm sure you've noticed, but the metroidvania aspect can make it hard to tell whether a certain powerup is required or I just need to try harder. Although the only time I've felt stuck (aside from trying to get to the top-right corner) was before getting the sticky upgrade, ended up doing something similar to hotfist's clip. On the other hand, now that I have some size upgrades, I've run into the opposite issue. It feels like I'm cheesing puzzles that were supposed to be harder, because I can often just build a path directly to the checkpoint or coin.
Other than that, it's great. Haven't beaten it yet but it feels like I'm approaching the endgame.