How to play Valhalla and the Lord of Infinity on Mac

You are the rightful heir to the Throne of the Kingdom of Infinity, but the evil Lords of Infinity have taken over and made a mess of the land. You must go after them and retrieve your birthright. The game is a top-down adventure using a joystick- and icon-based control system. When you walk up to an object you wish to investigate, press fire to gain access to the icons at the bottom of the screen, with which you can look at, pick up or use an object. There are also people who will talk to you. And I mean 'talk' - the game is full of speech for every action, including your character saying things such as "There's nothing here" and "I can't do that" in response to each instruction. Each level has one disk's worth of speech, and there's no disk swapping during the game. The level designs include hidden holes in the floor, but there are maps to locate these.