CeaselessSoul and I finished the game together, and here are some thoughts I have:
First of all, please please please DON’T have dying.
1. Racks up WOs
2. Takes 4 seconds to respawn, which becomes quite a long time when you’re repeatedly dying
Just :LoadCharacter() on the player when they hit a dying brick, and it’ll respawn them immediately. This is something I think about EVERY time I play an obby, I would absolutely love for you to implement this.
Secondly, the ending part gets pretty boring. It’s one of the best parts of the map, but finding the keys after checkpoint 45 just takes a long time and gets pretty boring.
Thirdly, there are a few mistakes in the map. At the end of the boulder drop hill, there is a large Z-fighting wall. Also, just before the bridge with the disappearing planks and ranger sword dude, there is an angled brick which you can climb to get on top of the map. I’m not sure if this is intentional or not (it kinda seems like it is, since I haven’t figured out another way to get the white key), but if you put a railing or something up top it’ll show you that you’re supposed to be up there, or, if you shouldn’t be up there, fix the brick.
Fourthly, you might want to consider doing something about the bosses. They aren’t that bad, per se, but they seem very automatic in just following you around and chopping when they get near. Also it’s pretty easy to get them stuck/avoid them, which is probably what you’re aiming for, but it feels more like, “Haha, I outsmarted the AI! Stupid game!”
Finally, I think it would be awesome if you had some sort of story here. The cutscenes and occasional bosses make it feel like it should have some sort of storyline, and it wouldn’t be hard to implement that. You could have NPCs that you talk to along the way, who guide you along the different obstacles. You could also have subplots, where you do a side obby for bonus points/badge/etc.
Overall it’s a great obby, much more enjoyable than most. Great scenery (skybox could use a bit of work, though), good job of guiding players along the path, good use of lighting, enjoyable obstacles. 
And here is a picture of the two of us at the end. 