Thanks for the review!
I actually don’t own ANY Commodore hardware, so it was written and tested in VICE. The browser emulator is a big buggy, but I can’t do anything about that ;)
It has been played by others on actual hardware, though: https://www.youtube.com/watch?v=IdGToEAd-hM
As to the background limitation, it was a technical one. I could only decompress and double-buffer the top 13 rows (of 25) before I couldn’t keep up with the buffer copy. Also, I used all but ~4k of the C64 ram, excluding only the I/O space ($D000). Using that memory would require me to refactor the game to only page that ram out when accessing I/O registers and I ran out of time. :)