No it absolutely explained it. Mind you it was a lazy explanation, but it explained it.
When the particle accelerator exploded, it not only caused a rift between those two dimensions, but all dimensions in the multiverse in all periods of time and space.
In other words it ---fouled up beyond all recognition--- up everything, and every movies' monsters/wierdness/whatever is a result of the explosion. The next film is even set in world war two, because that space-time distortion messed up the past as well. So there isn't a timeline and the films might not even take place in the same universe. But if you want to go there, you could assume that Cloverfield happened first, then Cloverfield Lane, then Cloverfield Paradox, which cause the explosion and created rifts in the previous two film's time periods allowing those monsters to exist at that point in time.
Yes it's confusing, but it is a paradox... it is supposed to be confusing.
Anyway, like I said, yeah it isn't too special, but worth a watch to kill time. If anything the pacing and structure made it more like a slasher flick than straight scifi/horror. That isn't a bad thing, but we know all the troupes, so it doesn't really have any surprises.