Using the same graphical interface as Deja Vu, Shadowgate is an adventure game set in a fantasy world. Players take the part of an adventurer sent to the ancient keep of Shadowgate on a quest to find a mystic artifact known as the Staff of Ages and stop the evil Warlock Lord from summoning a horrific demon known as the Behemoth. However, Shadowgate has become infested with the Warlock Lord's demonic minions, not to mention the castle's still functional booby-traps.

Unlike Deja Vu, death comes at the protagonist suddenly, unexpectedly and, most of all, often. Such simple acts as pulling the wrong switch or opening the wrong door can cause the hero to be skewered by a booby-trap or disemboweled by a monster. If the player character's torch burns out (this happens quite regularly) and the player forgets to light a new one, the protagonist will trip in the dark and break his neck.