Not sure if I have posted this before, but a while back I got the final missing Wonder Boy game for my collection - Game Gear Monster World II Dragon no Wana.
The game was obviously originally intended for the Mark III (it has the Japan only FM soundtrack and the title Monster World II in the ROM if played on a Japanese system), but was cancelled, and only made it out in Japan on Game Gear.
It was a nice touch that the alternate cover art for the Dragon’s Trap remake in Japan is the GG art with the original Japanese title!
Now I have the whole original Japanese Westone set!
Plus their weirdo PC Engine/Famicom cousin versions too.
Edit: Ah crap I forgot to include my copy of Wonder Boy SG1000 in the photo. Oh well, I found I posted that four years ago here