The story of Quest for Yrolg begins with a necromancer who is about to finish a ritual that will make him the owner of the world. Players control the necromancer's assistant, a puny little demon who has the important task of preventing three heroes from reaching the demon's boss and killing him before he can finish the ritual.
Players can move with total freedom through the necromancer's dungeon, interacting with all of the objects they find there. You can speak to the dragon, ask a golem to follow you, grab a vorpal sword... but you can't directly attack the heroes. Your objective will be to set traps for the heroes.
You can, at any time, ask your companion (a red cup), to let the heroes in, at which point your traps will be put to the test.
Quest for Yrolg is a great graphic adventure that not only offers an interesting story and fun game mechanics, but also has great visuals.