A first-person, timed underwater escort level with stealth. There are no checkpoints, added momentum to your controls, and constant environmental hazards that kill you in one hit. When you or your escort are caught by one of these hazards, there is a long animation with slow, brooding music as the screen turns red and you slowly surrender.
If you move too far ahead, your escort gets lost. You have two movement speeds, the escort swims at a speed between them. There are also awkward camera controls that irrationally zoom in on unimportant objects, and random artsy angles which show nothing at all. Every few moments, you must stop to use a breathing apparatus. The timer, which starts 3 minutes before the level begins, is 10 minutes long. When the timer reaches 7 minutes it begins beeping every second. The beeping is in the sound of a bicycle horn.
There is a seemingly unimportant plot item near the start that you aren't told about until near the end of the level. You use this item to fight a boss you have previously defeated.