I still have the music and SFX I made, but other than that no word from the other guys 
word
from one of the other guys
sorry, life has taken me on a long detour.
I've started porting the code to RP2040, from which I will be able to debug. I kept running into random issues, and being unable to debug made things difficult. I am hoping the rp2040 will be a better platform in the end. It does not have the tilt sensor, but perhaps that can be added on if desired.
Recently experimented with playing stereo mp3's from an rp2040 using SDIO and that worked just fine. This could mean fewer parts and less complexity. The rp2040, being dual core, means I could also split the work and not worry about spotty music playback or carefully timing things to ensure that various bits of game code don't interfere with data pulls from SD.
I got a lot of things on the go, so this will not progress quickly, but it may progress.