I would have been your daddy, but......nah...
--Sgt. Johnson
there are two big secrets, a ghost with a sword in the area above the stasis with the flood, which can only be reached by using the gravitatory lift in the floor, then directly jumping and using another one that is nearby. the other secret is the big box in the half were there is no big monitor, to get inside, there are some nodes on some columns near the big monitor. one leads nowhere, and the other one leads to the box.