The theme is great! I think it matches the theme of the jam very well, as it mainly centers on how ocean pollution affects sea life in a comedic way.
The gameplay is great, with a few notes. The player is very snappy and responsive, however the animations have some bugs. The enemies don't really have a telegraph when they will change directions, so you do have to actually watch them and learn their routes.
Aesthetics are great! Love the sealions and how the player changes in different zones!
Writing is excellent as well! The game has a "Story" button in the main menu that explains the story behind the game, which articulates it very well.
Overall polish is good! Obviously as a game jam game there isn't a whole bunch of polish, but I believe that for a game jam game it has far more polish than it needs!