I'll add some deep thoughts about my opinion of story mode and why I think it's completely seperate from the arcade ladder that will also most likely be in the game.
So this game has all/most of the characters and stages from MK - MK3. I really think the story mode takes us through the long journey of each tournament MK, MK II, MK3 and it sort of "holds our hand" as we go through each one. I think we'll play through the original MK tournament where Goro/Shang are eventually defeated and I think we'll see a similar chast of characters in this part of the story... but I think it will be a linear path and we will be presented with the end game scenario. The story mode will then progress into the MKII timeline and we'll see the familiar Outworld MKII levels and also be introduced to new characters that weren't in the first part of the story. I think it plays out this way all the way through the end of the MK3 events, with new characters and environments opened up all along the way. And in the end it will all be the big grand (15 hour) story that NRS wants us to see.
One of the main things I have to back up this theory: The cinematic trailers
Sub-Zero: Scorpion says: "You are not sub-zero". Sub zero: "My brother participated in this foley, I fight for his honor"...they are in Kahns arena when this happens... perhaps Scorpion kills the original sub zero as part of the first tournament story line... he is then questioning this "new" sub zero in Khans arena in the 2nd tourney. Why not? Sub-Zero is admitting his brother participated in the tournament... Scorpion knows this isn't the sub-zero that he once knew....
Scorpion: "This is where I was reborn... this is where you will pay". It sure seems like he is talking to somebody that should know he was once dead... the original sub-zero would know that and it also supports my theory from above!!! Makes perfect sense to me that he would kill sub-zero here and then question the new sub zero in the MKII tournament!!
Mileena: Johnny Cage asks: "What are you doing out here"... "Looking for a new playmate". Seems to me like this is where Mileena is introduced into the game cause Johnny isn't sure who she is. Looks like an MK3 stage too, so maybe she doesn't come into the story in MKII anymore.
Besides the cinematic trailers, we see some other things like Kitana chained up in Khans arena instead of Sonya / Kano as it was previously. Very plausible this is done on purpose and that she will be introduced sometime during the events of MKII or perhaps in MK3.
Surely I'm not the only one that thinks this is all possible... seems very likely from what I've seen. The whole time-travel thing has really opened up all possibilities and they can really do so many things here. But all in all, I think I'm right when I guess that we will see a very static story line that introduces characters/places/events in a very linear fashion that follows the same premise as before, but with lots of cool twists and additions along the way. I'm super pumped either way!!!!