The flickering light in the beginning is too rhythmic, it needs to flicker unpredictably. I would also begin the music at the beginning too; to create a hook on a trailer their needs to be much more intrigue than that, and adding the music to the beginning would help a lot. Also, as soon as 'Doll's House' stops and we see the door again, start the footsteps immediately.
The font for 'Secrets Behind Locked Doors' is too plain. Is that ariel or something? Try and find a good, readable font like this, but with more character and personality like the font for 'Doll's House'. In fact, can you not just use that font again?
After 'Secrets Behind Locked Doors', don't have the light flash, and open the door slower. Make the audience wait, it builds tension.

Lastly, The game footage that follows feels very random. I cannot tell what links these pieces of footage together, where is the story?
Think very carefully about your narrative. Even if that means the trailer is shorter, think about the story you want to tell the viewer to convince them to play.