Knightmare II: The Maze of Galious

"Knightmare II: The Maze of Galious" (known in Japan as "Majou Densetsu II: Galious no Meikyuu") is an action-adventure platform game that was originally released in 1987 for the MSX. It can be considered an early example of a Metroidvania-style game in which players can freely explore a large castle.