if there was a game it could be like this:

At the beginning you can choose to play as Rob,Hud,Lily,the monster,or one of the spiders things.

Spider story:You go around searching for targets for the monster and just killing everyone.Or you could just roam around and explore the city.abilities:bite,climb on walls,night vision.
Monster story:Go around just destroying everything like a 3-D horror version of Rampage.abilities:a death beam(like in halo 3),destroy buildings in 1 swing,eat things.
Rob story:You can either choose to escape or go to save your wife(we all know how that turned out:BOOM!)abilities:run away lol,kill the spidery things with items from stores,punch,kick,jump,use cell phone to call military to your location,hide from spiders in different items(boxes,trash cans..etc.)
Hud story:You video cam everything while trying to to get to Robs wife.abilities:run away,kill spiders with items from stores,punch,kick,jump,use camera to gather information from people and soldiers for the government,hide from spiders in different items.
Lily story:You leave the party and drive your car to your apartment then get attacked by the monster*cutscene*Robs crew comes,saves you,then you try to escape.abilities:run away,kill spiders using items from stores,hide from monster in different items,punch,kick,jump,use cell phone to call military to your location.

There should also be a multiplayer mode where you can have up to 4 players using all the different characters to follow the story that the player using Rob chose(escape or save wife)*

*Xbox Live Exclusive: Play on-line with different with different servers with up to 10 people(Monster,Rob,Hud,Lily,and six of the spiders).It could be Co-op or Survival.Co-op:Whoever chooses Rob chooses to escape or choose his wife while the players who chose Hud and Lily follow Rob around and help him.Then whoever chose the Monster would just destroy the people and buildings while the spider players would go around roaming the city findings targets for the monster player or just killing all the people in the city.Survival:Everyone picks their character and then has an all out battle between all the other players(like in halo multiplayer battles)