You start out in investigating your home village. Somewhere in the village you will find your brother Luziris. Approach him and press space to talk to him. Do not leave the village until you have talked to Luziris!
After you have talked to Luziris, leave the village and head south-east. Use the compass and the automap to keep from getting lost. You should eventually reach the town. In the town are many people. Talk to all of them. You can get some quests here. Joining the magic guild is technically optional, but the game is ridiculously difficult if you don't. Rest in the inn, buy a healing potion if you can afford it, and head north to the green cave to grab the fungus. Click here for a map of the green cave. The other guild quests are truly optional, although profitable. When you are finished, head south from the town to find the dragon. Click here for a map to find the dragon. Talk to the dragon. The dragon will ask you to fetch four gems in sequence.
The orcs have the first gem. The orc village can be reached by heading north from the town, then far east. Talk to the orc cook, then leave the village and head south and east again to reach the beetle cave. Collect all ten beetle eggs and head back to the orc village. The orcish cook will give to the key to the orcs' dungeon. Enter the dungeon, then press space on the north wall to open a secret passage. Get the gem. Also free the little boy from the dungeon. While you're here, you can also fight the dwarves (but make sure you have enough healing potions).
The second gems is held by the frostmen. The frostmen's lair is somewhat hard to find, use this map (western exit) if you need help. Getting the gem is fairly straightforward - just fight the frostmen until one of them drops it.
The gnomes have the third gem. Take the same path as you did with the frostmen, but take the eastern exit in the place with the violet walls. Watch out for gnomes that like to teleport behind you!
The fourth and final gem is in a cave next to the temple. The temple itself is in the same general area as the dragon. Use this map again if you can't find the temple. The cave itself is fairly easy to navigate (although it has some truly nasty monsters).
By now you should have a good idea of how the rest of the game will flow. Before you enter the temple, you should have at least one of the advanced spells, plenty of healing potions, and possibly a ring of protection. Run through the temple to enter the catacombs. Some of the coffins have buttons that can be pressed to reveal more of the catacombs. Do this repeatedly until you have made your way through the catacombs, and head for the lower crypts. This is a short but very dangerous area. In one of the crypts is another button on a coffin that opens the hidden crypt with the medallion of water breathing.
Enter the underwater area through the well in the town. Only the snowball and death bolt spells work correctly under water. Head west, north, west, south, and west again to reach the sunken city. Enter the big building in the center and press the button. Now enter the southern door, go east, enter the niche, and press space to reveal a secret passage. You will need to press space repeatedly on different walls to progress. Here is a map. At the end of the passage are the stairs to the dungeon. Enter the dungeon, take the western passage north, press space on the wall, go east and enter the northern triangular room, and press the button on the northern side of the inner triangle. Go back to the western passage, and enter the north-western room. There is now a passage here to the secret treasure chamber with the amulet of unlight. Look at this map if you are still having trouble.
Before you do this section, complete any quests you want to complete and spend all of your money. You won't be coming back. Here is the map of the violet area again; this time head north. Make your way through the maze to the castle. Walk straight through the castle to the throne room at the north end, then head east to get to the basement. Head north again through the yellow portal to reach the cloud area. This is the last area. Clean up the weaker enemies before you fight the boss if possible. When fighting the boss, keep your distance. Once you've defeated the boss, open the door at the north end and slowly approach the portal to finish the game.