this was such a nice and charming game to go through! its crazy how much you managed to put in this game, from the scale of the island to the 3d models you made! it seems like theres even a lot of underlying systems in the game, very nice! the foundation for a nice action rpg is there since a lot of the major systems seem setup already, though there are quite a bit of issues that stack up and should be addressed first (nothing too game breaking).
like some of the people have said, the inverted camera controls felt hard to work with for this type of game at least. mouse sensitivity also felt a bit high for me (though that could just be on my end), so having both of those be in an options menu would be great! some visual communication adjustments could also be appreciated, like showing what you get in the chests (even just saying it as world space text), since im not too sure what i got most of the time. there was also a point where i think i got xp from a chest and leveled up instead of down, which made me lose the skill i earned earlier (though not too big of a deal since i got it back, but weird for the chest to kind of nerf me). there was also an audio bug when approaching the chest where it seemed to play every frame. lastly, the enemies (especially the shadow one) sometimes dealt damage to me without going through its attack animation which led me to dying a couple of times because of it (though i am fully aware how hard the Unity animation system is to work with xd). so yeah, a lot of small issues, but them stacking could lead to problems overtime so it'd be best to address some of those QoL issues first when developing!
enough of the negatives, the general RPG system is sick! i can't say i played a game with a leveling down system (though i think i've seen some before), but i like the trade-offs of leveling down and the in-game context behind what it means to " level down", very cool! i also like the how cooldowns for skills don't reduce while attacking, thus informing the player to not just spam attack and swing randomly, i think thats a neat design trait of this game! also the non-humanoid enemies look really nice! the ones that are in the game rn have nice custom animations that im surprised exist due to both the jam duration and the amount of other content thats already in game! the environments in the game also look really nice, i was always surprised when entered a new area!
overall, this was a fun and campy world to go through, i think it has a lot of potential! from the dialogue and the animations, seems like you had a lot of fun making it, which really shows while playing the game, great work!