Nautilus

The Nautilus has lost power ninety metres under the North Sea. The captain is gone, the reactor is counting down, and the escape hatch answers to a code nobody wrote down.

Four puzzles run at once, the room changes as you solve them, and the lights tell you how much time is left. You will need every pair of hands and a calm voice.

Our hardest room: seventy-five minutes, three players at least, and best after a few games. One step down into the hull, so not step-free.