The visuals and systems feel very professional; I wouldn't be surprised to see these in a published game.
Unfortunately I drowned in the first underwater section, because I couldn't figure out how to ascend or descend; it's pretty tough to have a time limit when trying to figure out new controls without a tutorial! I absolutely get that it feels much nicer to be able to navigate the ladders above water with the ordinary direction buttons, but it might still have been best to force the player to learn the up and down controls then, rather than only requiring them when drowning? Also, I'm not sure whether you were able to implement saves/continue points (there is a "load game" in the main menu, at least?); if you were then I think one before the first drowning section would have been a very good idea (or even before the first combat; ideally you don't ever want players to be replaying the early sections of the game that have no challenges).
Still, a very solid entry overall (and of course as I've mentioned I'm a huge fan of the verticality), so great work!