What a fun game! Art style is perfect, upgrade system is fun, controls are intuitive! (Sorry, I don't know if the sound/music was good. I had it muted, but I'm sure it was great too!)
You mention sending it into space on a dusty cartridge... *could* this be released as a .gb, .gbc, or .gba file so that it can be played on a dusty cartridge?
This looks and feels so Gameboy-y, but I'm guessing it's more than a Gameboy could actually handle. But... had to ask.