Great game, and amazing theme and genre interpretation!
But I have to be honest, after probably over 3 hours of stumbling around and getting hounded by the (admittedly very cool looking) whale... when I found out I needed a second half of the pearl, I was very close to giving up. I did manage to find it in the end, though, and I recorded a little video guide for others who might be struggling! [SPOILERS] (Forgot to make it public, oops!)
The presentation is absolutely gorgeous. I adore the designs of the main character, the familiar, and the shopkeepers, and even the enemies were pretty cute too! It's really impressive how all the models, animation and sound work together to create the underwater setting, even down to details such as the protagonist's floating hair. The soundtrack is lovely too, especially the music in the dark zone and the big trippy ocean level with the yacht!
All the movement and combat looked and felt great as well, though I wish health pickups were a bit more common. I feel like in a game like this, it'd make sense to regain some health after picking up a certain number of shells. The magical girl transformation at the beginning of the level was adorable, but after a while I did wish I could skip it. I also noticed the cat familiar would often get stuck on obstacles and left behind.
On the other hand, the collectible outfits were a great touch! I managed to find all but 2, and my favorite by far was Potential, which I think might have been based on Madoka Kaname? Might be wrong, though!
It was immediately very unclear what to do in the first level (or should I say the overworld/hub area), and had I not read the description, I'd have assumed that was the entire game. The spiral water currents really looked like something I should've just been able to jump into and get launched by without any upgrades. I wandered around for probably around half an hour, and I did try to interact with the black boat a couple times before discovering by chance that I was meant to jump on it.
In general, it took a lot of trial and error to find out how to get the most out of my vertical and horizontal mobility. And even having a rough idea of what my character was capable of, it was very hard to tell whether I was making progress, going down an optional path, or sequence breaking. That first pearl half location in particular was something I had initially dismissed, since it felt like an optional challenge that'd have given me an outfit or a health upgrade.
The giant enemy chasing you for TAKING TOO LONG is a cool idea on paper, but in practice kinda feels like it's kicking you when you're already down. Since at that point you're probably already very lost and unsure where to go, or failing some platforming section for a very long time, and now you're also dealing with having to figure out how to get back to where you were.
The final boss was not what I had expected, and a wonderful conclusion of the game! The sudden change of camera was very confusing at first, but fortunately it didn't take long to get used to it. I liked the variety of attack patterns, although I think either I was a bit slow to beat the boss or it could do with a few less hit points, as towards the end it kept repeating the same attack (rapid teleports followed by a melee swing).
Overall, one of the most polished and complete-looking games I've played in the gamejam, in terms of look and feel! But with so many cool-looking characters just kinda hanging out there, I think it definitely could have used some more dialogue to tell you what even is going on while subtly pointing the player in the right direction. Regardless, great job!