Gandalf the Socerer is a single screen shooter viewed from behind the castle walls looking out into the land, where you play the role of Gandalf and you must protect your castle from attack by Lizardmen trying to get your treasure. Gandalf starts on top of the castle walls and tries to destroy the Lizardmen who appear from the woods and move towards the castle by moving a crosshair and blasting them with fire. Any Lizardman destroyed leaves behind a gold coin. If you miss any Lizardmen, then they appear at the door below and attempted to open it while an apprentice stirs your cauldron nearby. As well as your treasure you must protect the apprentice because if he is taken then he will be held for ransom for your treasure. Once a Lizardman gets through the door, you can go below and kill him but if he takes the apprentice outside the castle then you can follow him outside. The view switches to a single screen isometric view and here you must kill the Lizardman as well as any others and lead the apprentice back to the castle. There can also be gold coins to collect left behind by any destroyed Lizardmen when you were in the castle. The Lizardmen blow fire at you and if you are hit then it is game over. If you lose the apprentice then another one appears when you are back in the castle and you are only able to lose three before it is game over. Your fire is limited and each time you use fire then it decreases but if you climb up to the top of a tower then you can replenish your fire.