I've already shared some of my thoughts in discord, so I'm gonna try to be quick here: Great job! I loved the music and the artwork for the player and the main terrain. The size and amount of content in the game is definitely very impressive for a gamejam, and the world is just big enough to get a bit lost in (yet not hopelessly so). The controls are nice and snappy for the most part, and I'm a fan of the player's speed (although it does make it hard to land some of the more precise jumps at times).
I liked the variety of the bosses, and some of the fights were pretty intimidating at first. The baddies are certainly on the tankier side, and sometimes it felt like they had twice as much HP as they actually did because of the lack of visible healthbars and the tiny range of your attack. Though, it all kinda went out the window when I realized most of the bosses could be brute-forced by standing next to them and using Lifesteal.
I liked the clear sense of distinction and identity between the different color-coded areas. The map overall had a nice sense of flow, being framed by the two tall shafts (one being part of the green zone, and the other connecting gold, green and orange). That said, some of the rooms felt a bit too big, especially when it comes to some of the climbing challenges that were essentially just a lot of small platforms stacked on top of each other.
Also, a small nitpick that's more of a Godot/Windows issue than a fault of your own: If you export the game as a single executable (just the .exe, without the .pck), Windows will get confused and show a warning before running the game. Even though a single .exe is obviously more convenient, it's still safer to export normally with a separate .pck.
Regardless, I had a lot of fun and ended up beating the game twice to see both (some?) of the endings. Well done!