I didn't know Sega CD games worked in Picodrive, cool!
I'll have a few more games to play now, cheers!
There is a small problem with them. The CD Audio doesn't work properly, apparently it won't work from either (complete) bin or mp3 set. In most games it only means no music (if they use CD Audio for music), but in Snatcher it means the game will hang during some cutscenes which do use CD Audio. The few cutcenes which do use them are synced to the audio track and without it the game hangs. I don't know how things work when you include both a (complete) bin and the mp3s, rather than incomplete bin and mp3s. Though I assume it won't make a difference.
As for Popful Mail, there was no sound in the first (FMV?) intro, though there is sound (and music) everywhere else (including the cheesy game intro right after you press New Game).