You've woken up in Hell! And being a ghost. And finding out the natives are hostile.
The object in each level is to find the key, and then find the door it opens to descend another level. You can move to adjacent spaces by clicking on them if they're clear, or unexplored. Orange areas are places you can move to, red areas are places you've uncovered but are too far away to reach, and gray areas are places you haven't explored yet. Each time you move to a new place, all the nearby spaces are uncovered, revealing whatever dangers or items there are.