Troll (UK) (1988) - Amstrad CPC - Action, Platformer

Humgruffin the troll has been transported to a mysterious world called Narc, a strange land of crystal caverns populated by goblins. His only means of escape is to collect crystals. Each cavern has a floor and a ceiling, and by stepping on a pyramid, you will be transported between them. There are also magic holes which will transport you to another cavern; you can also create these holes yourself, and stepping on a toadstool allows you to change their behaviour.