It feels really fun. The achievements are a nice touch and I feel play into the theme (not the achievement system in itself but what it asks of you). I would say a good small balance would maybe make upgrades 3, 4 and 5 of the tentacles more expensive since as it is Tentacle level 5 makes the stomach upgrades irrelevant.
However it's incredibly fun to rip and tear those poor lake wild-and-not-so-wildlife. I'd also say removing cast shadows entirely would probably play into the N64 era a bit more though to be fair some games did have "fake" cast shadow.
Last small note is about the description. I don't know if it was Unity Input system messing with my computer, but Back was actually Left Alt instead of Left Ctrl for me. Also ran into a very minor glitch. I had to first unequip the straw hat you unlock by consuming your first lakegoer. It was automatically equipped at the start and starting the game with it made my hunger bar instantly empty, but it didn't bring me back to the menu, and I couldn't attack anything. Kind of like a freeroam mode. It did however fix completely and instantly when I unequiped/try to equip another hat.