The art direction is beautiful and consistent from start to finish. Everything looks pencil drawn in a notebook: the menu is a sheet with crooked edges and a shadow, the scenery has paper texture, the clouds and sun are scribbles, even the studio screen ("ABProjects, drawn into existence") stays in character. One of the prettiest and most coherent entries in the jam.
And the enemies are ERASERS. The counter in the corner says "ERASERS 5" and you die by being rubbed out. In a jam about games being erased, making the eraser the enemy is the most elegant metaphor anyone here managed, and the lose screen doesn't say Game Over, it says ERASED. That's the whole jam in one word.
The end of run report is fully themed too: Wave, time, Score, Erasers defeated, INK COLLECTED, Ammunition crafted, Health restored. Even the currency joined the metaphor, ink instead of money. And having a CREATIVE MODE in a jam entry is pure generosity.
Three notes. The game pauses itself every time the window loses focus. That's correct behaviour in general, but it happened to me constantly and really broke the rhythm, so maybe pause only when the tab is actually hidden rather than on every focus loss. I survived 30 seconds without defeating a single eraser, they come fast and the aiming asked for more precision than I had, though that's partly on me. And it wasn't visually clear how much health I had, since the HP in the top left is small and crowded in with other numbers.
This is my favourite art direction in the jam alongside Zariel's Lair, and yours has the advantage that the art actually serves the theme.