...Ok, so...
In the really late game, when it starts to lag, the fire rate takes on this cool triplet groove that I couldn't get out of my head. I ended up making a beat out of it. Can't post it in the comments here, but it's in the Jame Gam discord in the #showcase channel.
Viewing post in Lost In Space (Mini Jame Gam #39) jam comments
Hahaha yeah I planned on adding some more late game (something like a prestige that reduces spawn rate but makes them stronger, harder, etc) but ran out of time, so I figured that the real "win" is when you lag so hard you can't play anymore.
Also, that song is amazing!! FYI - all sound effects were done with https://sfxr.me/.