This is not at all what I was expecting. I'm not sure what I was expecting, but it wasn't this!
I'm mightily pleased that I managed to finish this because I quickly got the impression that it's a tricky game. I managed to one-shot the first two levels and the third took three attempts. This doesn't sound or feel too unreasonable, but it definitely felt tough.
My strategy in the end was to more or less treat the two tentacles as a single entity, move them close to one another slightly offset and then just repeat the same movements for both hands. I think realistically that's the way for most people to get their head around it, as the mental dexterity to control both independently isn't too common naturally without training it. I didn't engage with the dive mechanic at all as I was a bit overloaded.
I think with the power of hindsight, I might have preferred the main game to just have had a single tentacle and perhaps you could have had an 'insane' mode or something with the double in there? Not too sure. Regardless I managed to finish it, so the tuning is alright for me :D.
I like the graphics and audio, it all felt nicely cohesive and nothing felt out of place. I really like menu system; sure there's the small menu bug, but that's hardly an issue. The tutorial was great for me; I know lots of people hate written tutorials, and while something within the game itself is usually better, I felt you laid everything out with clarity and brevity. The little niceties like the volume sliders and even alternative music is a lovely touch.
The gameplay loop itself is really engaging, like face hugging the monitor engaged. It's stressful and difficult but that's kinda the point. It held my attention and felt great when I cleared a level. I note some other commenters had problems with creating whirlpools, but I had no issues, so I guess mileage varies on that one.
I think the game is the perfect length, and it doesn't overstay its welcome at all and ramps up in difficulty nicely without spreading itself too thin.
I think truly the only weakness is the ambidexterity requirement. It's something that people either have or they don't. And in the context of the jam, it might not be something people can pick up fast enough. As such I imagine there's a portion of players who've picked this up and just bounced right off. It's no real fault of you, just a difference in one's brain I think. I myself made my game way too hard and largely impossible without instructions, so I definitely feel the pain of making something that no everyone is able to play and complete.
However, I enjoyed this, and found it very satisfying to complete. It's an underrated gem for people that enjoy these sort of chaotic hand-eye game. Thank you.