It's pretty fun once you max out all the upgrades and not gonna lie, I'd say that managing oxygen and swordfish become harder with more upgrades because of collision tracking making it so that it's more likely your shots get blocked by something the more efficient at killing fish you become, so in a way, it's interesting how the endgame doesn't just get rid of all the difficulty, but forces you to be a bit more careful with your shots. I wish it was more obvious the upgrade tab was scrollable and that harpoons were just autofire, because they're endless anyway so the only thing limiting their rate of fire is wrist pain or hand pain.

Really cool game !
Love what you did with the assets <3

Little feedback : The game over condition feels a bit sudden. Since there is a lot to keep track on screen, it's easy to forget to check the health and air level on the bottom of the screen.  Adding a more visual indicator (screen going red or darker, or a HUD on top of the player sprite) for when the player is about to run out of oxygen or health would be a real + if you plan on updating the game after the Jam.

Great work !

Very cute! But I feel like it ends before I can buy or do anything