Diveman

A platformer where you must switch between five different characters, each with their own unique ability, in order to pass obstacles. It's more well-known by its hacked variant, Wonder Rabbit, which is seen on many dreamGEAR plug & plays.

Gardman is actually not the original version of this game, nor is Wonder Rabbit. As seen in the CHR data of Wonder Rabbit, the game originally starred Pokémon, with Pikachu, Nuzleaf, Combusken, Marshtomp, and Hariyama. The latter four would later appear in Monster Brother, another Gardman hack, but Pikachu did not. The Pikachu version has still not been found, and may have never been released.

Source: TheGamesDB