Stylized titles shown before the film starts.
The titles give a sense of sinking, and being isolated and trapped. Making the use of so little.
Thrilling music building up suspense. Quite minimal.
Brings up the idea of death and never being found again.
I think this is especially effective because it doesn't give anything away and makes you think more and imagine whats going to happen. I especially like it because of the slow build up and mysterious music.