I am a bit on the fence having found out the Movie was shot before as a completely different movie (Cellar) and then they have just cut some scenes, added some scenes to make it somehow tie in with Cloverfield....
I think it could be a interesting concept as far as the Doomsday Prepper Bunker and the handful of Survivors.... but i think only the end of of the movie we shall see what is outside and this would be when we would see what ever links there is to Clovefield.
But again i would not be expecting much.... if they go for a Big Monster then i would not be suprised if its only shown for a short time like the End of Cloverfield after it brought down the Chopper.
If its going for the Slusho has turned people into Hybrid Mutations, then i also think we would not get shown much of this..... i expect the Climax of the Movie to show the few survivors to escape outside and then Spot the Horrors outside and cut to Credits...
Pretty much as in a Short Scene like for example the End of Planet of the Apes 2001 when Mark Wahlberg's Character thinks he has returned home, only to then find the place is still ran by Apes.
Or the ending of the 1968 movie when Charlton Hestons Character comes across the Fallen Statue of Liberty....
So i expect a small reveal scene like this... than a movie that would cover the new Monster or Monsters on screen for a while.
I am going with maybe Mutant Hybrids, and that way JJ Abrahams can Gauge Fans reactions to the reveal and then determine if he did another Cloverfield movie, if fans would be pleased with going for the Aftermath of 10 Clovefield Lane Scenerio... or follow on with Cloverfield Scenerio.