I defeated 22 Jeremies! There was a good amount of strategy here for how seemingly simple the gameplay is. In order to defeat the more difficult Jeremies, you have to carefully consider their upcoming moves and use your blocks accordingly... I found it best to save up a lot of attacking pieces over time to try and take Jeremy down in one hit, avoiding having to bypass the armor repeatedly on different turns. This meant that Jeremy's healing turns became good chances for me to build up shrink power or attacks before I have dealt any damage.
I liked the Tab key hints, and it's nice that they highlight everything. Hiding the hints most of the time also keeps the screen clean and clear. But I wish the blocks would maybe snap into place a little easier. It can be a bit difficult to move the block just enough to not touch the wall without having it touch another block. There's other small UI/UX things, too, like the blocks spawning on top of the piece frame, but these are mostly just nitpicks.
I also like you only have the power to shrink the blocks. A lot of games in this jam give players the power to scale up or down, but making larger pieces an undesirable effect controlled by the AI is a cool take on the theme.
With more features/polish, I think this could be a really engaging puzzle/strategy game!