Now that was a feast of a metroidvania, so intelligently designed! Had a blast playing the game, from story, to platforming, to progression, it was all either good or great. The platforming and movement upgrades were very neatly/smartly designed, and while I didn't realize the sequence break that you mentioned (I saw the video in your reply to someone else), I could definitely see how the movement tech could lend itself to really interesting sequence breaks.
Don't want to nitpick too much about anything in the game since this is a jam with relatively small dev teams and all, but I would like to make just three minor criticisms. While the visual style was striking and pretty polished to look at, I feel like some of the textures' contrast could be softened, particularly the base cave tileset that you used. The stones' black outlines don't mesh very well with the relatively lighter tones of the tiles. If you ever get back to debugging this game, I feel like you could take a play out of Mojang's book and soften the stone tiles out a bit, kind of like they did with Minecraft's legacy textures for stuff like cobblestone, netherrack etc.
Another personal criticism I'd like to make is that the metroidvania aspect could maybe be a bit more pronounced? I don't know, maybe I've just played too many metroidvanias and thus know how their design directs players to the next upgrade, but the road ahead always felt very linear and obvious. I don't think I ever even saw the other upgrades' before finding the previous one in order. The existence of the aforementioned sequence break is fine and all, but I feel like there should be just a bit more baked-in backtracking just so the player's spatial awareness is tested a bit.
Also - this is easily the smallest problem and didn't really hinder my experience but I'd still like to make notice of it - the map wasn't that useful for 100%'ing the game since it doesn't actually mark where you saw an item, just where you have collected one. While I do understand it's supposed to be just for knowing where you don't have to look, it feels a bit counterintuitive to have a map that doesn't really have much of a use until after you've already gotten said item.
But again, I really did have a phenomenal experience. This was easily one of the better metroidvanias I've played on here, and I absolutely loved the Steamworld Dig-like setup of the game's world! I only focused more on the negatives because all the countless positives are so obvious to anyone who has the honor of playing this great game.
