Game Boy

Castlevania II: Belmont's Revenge

Trivia

It is a bit confusing, but Konami actually made two different games called Castlevania 2:

Castlevania 2: Simon's Quest (NES - 1988) is the sequel to the original Castlevania (Arcade, NES - 1987, DOS - 1990) and stars Simon Belmont as the main character.

Castlevania 2: Belmont's Revenge (Game Boy - 1991) is a sequel to Castlevania: The Adventure (Game Boy - 1989) and its main character is Christopher Belmont.

Belmont's Revenge consist of a series of tradtional levels while Simon's Quest allows you to freely roam the land of Transylvania. It is much more non-lineair.