I collected shells! So the swim mechanic was intuitive, though probably would feel even better if you added some deceleration over time, to help express that "floating through water fantasy" that this game tries to fulfill. I found collecting the shells difficult, I ended up just holding both clicks down and trying spin my way into shells to collect them - but I felt it would have been cool if it was more about clicking left and right mouse at the right time instead.
This game definitely starts to explore some interesting mechanics - i think it could be quite a fun mechanical game if you were to get the swimming feeling really good with momentum, and perhaps if you could have the tentacles reach to the cursor location to grab things (up to a certain distance), perhaps that could feel good. I'd also potentially look at reducing how much other shells block your movement. Perhaps running into shells and knocking them in a direction could be a strategy if you made the shells knockable.
Thanks for taking part in the jam and sharing your progress on the discord throughout.