Just to report that I can't have the game work properly with the multiMVS, as I metionned on hoffman itch.io page. BGM music is not played in correct order, and I encounter lack of foreground layer in levels 2-1, 2-3 and 3-1 (haven't tested beyond).
The game works perfectly with Analgue Pocket, and almost perfectly with my Flashcart for AES from competitors

. I haven't tried with my multiAES yet.
By the way, how works the FPGA file in each game folder? I manage to have BGM back in order by changing the number from 1337 to 12 or 10, but I don't understand why.