Kaeru no Tame ni Kane wa Naru (For the Frog the Bell Tolls) was an Adventure / Action RPG developed by Nintendo and Intelligent Systems, released (only in Japan) in 1992 for the original Gameboy. In 2002 a Game boy Color remake was announced by Nintendo, but it was soon cancelled, probably because of the release of the new Gameboy Advanced, that killed the final batch of GBC games. Thanks to Robert Seddon that has found some screens from this vanished GBC remake on GamesTM magazine #54, we can finally see the game in all its (cancelled) glory.
Update: It seems that these screens were just mockups made by fans of the original game and not from the remake. A GBC remake was really announced, but at this time there are still not any “official” screens from the project.
Thanks to Ita for the direct-feed screens and the informations!