Chocobo no Fushigi na Dungeon for WonderSwan

First portable entry in the Chocobo's Mystery Dungeon series. Released for the WonderSwan in 1999.

The story evolves from the opening movie when a fellow chocobo is "turned" evil by a crystal he finds in a garden. When the evil chocobo kicks you into a dungeon, the adventure begins. Travel through an ever changing dungeon, collecting items and weapons to become more powerful, so you can defeat the increasingly difficult enemies.