King's Quest 6 is better about it, but there are a few zombie states I can think of. However the game does its best to warn you that you'll have a bad time. Any of the following, without the right items will make sure you can't finish the game.

- Going into the catacombs on Isle of sacred mountain (specifically the hole in the wall is what killed 10 year old me) - going to the land of the dead (funny enough with coins that you need to get from the catacombs) - going into the castle (short or long ending) - telling the druids you're selling these fine leather jackets