Castelian

Castelian is a puzzle platformer video game developed by Bits Studios and published by Triffix Entertainment for the Nintendo Entertainment System (NES). The player controls a character named Julius as he navigates vertically-scrolling tower levels, jumping between platforms and destroying obstacles to reach the top. The game features a unique mechanic where players must switch between two different characters, each with their own abilities, in order to progress through the levels. Castelian was released in 1991 and received generally positive reviews for its challenging gameplay and inventive mechanics.