What a fun little game! The minimalistic pixel art is great, and I love how the sound effects fit perfectly with the gameplay and visuals. I wanted so badly to press that red button (and I did at the end). 😆 Awesome entry!
Just a couple of suggestions if you decide to work on this after the jam: consider making the player a more distinctive color to contrast more with the enemies, as I often got confused about which character was mine. You could also integrate the button as a game mechanic instead of just an end-game goal.
For example, players could earn a high score by defeating enemies, gradually charging the button. Once fully charged, pressing it could wipe out all waves at once, giving a huge high-score boost—then resetting the charge back to zero.
Really nice entry—well done!