The trailer is very detailed yet it leaves more questions then answers. From what i can see in this trailer anyways Desmund has entered the animus , however though while he is in it the animus crashes some how and he is stuck in his mind. When inside his mind there are what seem to be mazes. In another scene he sees a room full of writing similar to the ending of ASS. Creed 1. Im pretty sure IGN will pick up on the trailer and do a recap with everything they find