Hammerhead has released the first full trailer for its VR game Syren, which is expected to be available in early 2017 for PSVR, Oculus Rift, and HTC Vive. The game places you in an underwater facility where creatures that seem to be the mythological sirens have been kept prisoner, but something goes wrong and they escape their confines. It does seem like you are alone in the facility with the sirens, and must survive against them. However these aren’t creatures of mythology, but instead results of human experimentation.
The footage from the trailer is pre-Alpha according to Hammerhead, which may explain some of the stuttering and weird movements of the sirens.