Through the power of google translate, save states, and rewind features, I've completed Popful Mail. I first read about the game back in my huge Sonic phase when I was 11 circa 2001 when I learned originally they were gonna swap out Mail with a new character who was gonna be Sonic's sister and was always curious about it.
I played the PC88 version on switch and not the Sega CD version, but I feel I have satisfied my child self's curiosity. It was very much a "my" kind of game. If you got a switch and like $7 to burn and the patience to constantly needing to translate things give it a whirl! It's got that old PC gaming jank!