I might as well post my theories here too.
- Dante is psychotic, his first debut trailer is actually him in the real world and the game will show things threw his perspective. To him, he may be a nice guy trying to stop the demons but in reality he's just some rampaging crazy man. Proof of this so far is that he's the only one dragged into Limbo which is a common case for those who experience delusions as they are the only ones who see them.
- As such (of the above), Limbo and Limbo City are actually one in the same. However, Dante thinks that they are two different realms with Limbo being a demonic realm and Limbo City just being a normal city. Because Dante is crazy, he perceives any threat towards him as being something from Limbo. Like the demonic cameras could be just normal cameras giving off sirens and the demon robots could be just simple police officers.
-Naturally, what Dante does in "Limbo" affects what happens in Limbo City. So, to him, things seem like they're going crazy but that could be just him causing alot of destruction and death to innocents.
-Another thing to note is Malice, the overall Big Boss that runs Limbo. So far, Malice is an invisible entity that distorts the city when Dante is pulled into Limbo. It could be that Malice is just a part of Dante's subconscious, possibly just a massive representation of whatever pent- up negative emotions he feels.
-As a bit of speculation, I believe that Pat is either one of two things: (1) An aid or sympathizer who was assigned to play along with Dante's delusion, or (2) a delusion herself that Dante has produced.
-And as speculated before, it could be that Dante isn't his real name but possibly an identity he had chosen for himself based on the real Dante. Furthermore, it could be that he's not carrying Rebellion either. Notice in "The Fight" trailer, despite a news broadcast warning about Dante, no one seems to notice him as he's walking. I don't know about you, but I'm pretty sure that a guy with a sword on his back wouldn't just blend in so naturally.