Really great game! I love mastering the level and combo-ing all the downward ring things that force you down! I also found the grappling hook to be quite finicky, maybe instead of checking if the player hit the target directly, you could use a raycast to check if there was contact between the player and the mouse pos? That might help smooth out the gameplay! And maybe in the future, a small UI thing could show what you actually claimed after a run! Like one time I beat my high score by enough to claim like 4 new upgrades, but I wasn't exactly sure what they were. Having some sorta prompt that tells you what you just claimed would be a nice touch! (Played it again and I see that you float back up to the surface which lets you see the upgrades which is nice, but I still think a prompt that shows what you claimed would be helpful!)
Overall, really nice game loop and really fun to master! Presentation is also great, especially the underwater assets! Congrats!