A first-person dungeon crawler

You awake to find yourself in a cemetery. How you got there is of no importance - how you will escape is an other matter. The gates are locked, the walls are high and you are in your final resting place. The night air is damp and cold and the sun has just gone down. You have 12 hours - until sunrise - in which to set yourself free and return to the land of the living. Should you fail, at dawn you will fall back asleep in your grave. Between the tombstone and the freshly dug graves, treasures abound to increase your wealth - if you escape - and open to that which would prefer to remain sealed. Edible treasures are your only form of sustenance - eat all that you find. Only the strong will survive in the clutches of blood-thirsty vampires, flesh-seeking zombies and other undead wanderers, who materialize in the night air and try to claim you as their own. Enter, if you dare, stonecold tombs, musty crypts, mausoleums, riddled with mazes to confuse unwanted visitors, and corpse-ridden catacombs that meander through the earth. Once inside, treasures and a clue or two will make your venture worthwhile. But don't be misled - a clue is exactly what it claims to be. You'll need a sharp mind to use it to your best advantage.