Finders Keepers
Platform: MSX
Region: Japan
Media: Disk
Controller: Keyboard, Joystick
Genre: Platformer > Adventure 
Gametype: Undefined
Release Year: 1986
Developer: Mastertronic
Publisher: Mastertronic
Players: 1
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The King of Isbisima has entrusted you, Magic Knight, with the task of getting a present for his daughter. He sends you into the castle of Spiteland, which is overloading with treasures to uncover. Whether you return with them to please the King, or simply flee with everything you can get, is up to you.

Either way, the gameplay is platform-based, with enemies floating around to rob you of energy on contact. There are also scrolling mazes to move through. As you collect objects (often by using some of the other items you collect, to create chemical reactions of sorts and adding an element of lateral thinking), you must try to trade them for the most valuable items you can get.

http://www.mobygames.com/game/msx/finders-keepers