Crystal Castles is an arcade game developed by Atari. It was converted for the BBC Microcomputer by Peter Johnson and published by US Gold. The game is played with an isometric view of the multi platformed castle. When Bentley Bear collects all of the gems on the current castle, he will move on to the next, more difficult castle. Wandering throughout the castles are a wide variety of dangerous creatures, which Bentley should avoid. From time to time, a magic hat will appear. If Bentley collects the hat, he will temporarily be invincible to the castles inhabitants.