Where can I find the multiplayer footage, or is it just co-op online mode?

This should be obvious but I'll say it anyway. Adding multiplayer does not mean that the single-player will be affected. There are special cases for certain developers and certain games. We won't know the affect of GoW3's multiplayer until we play the game.

And yes, there are good single player games out there. Some have multiplayer. Some don't. If you're swayed away from good sp games that also have mp, then you're missing out.

God of War Ascension is not a good example of multiplayer "ruining" a franchise unless there are two distinct games/campaigns which from a development standpoint means a division and typically a dilution of resources. One that can only be played by one player and the second that can only be played with more than one.

That's the basic model for the FPS genre, and to a larger extent, shooters such as Uncharted or Gears of War. In the instance of CoD, it was pretty clear that the single player campaigns were reduced to allow more resources to go into multiplayer, which in all fairness, is where the money for those games lies. Why? Longevity. Single player campaigns can be finished in a weekend. That's not worth $60. Most developers want players playing their games for as long as possible; few can rely upon the tried and true RPG design techniques that can stretch a game to great lengths.

RE5 was not an example of the single player mode being drawn down as it was a partner optional campaign plus an online multiplayer only mode. Sort of the best of both worlds, with the multiplayer mode being a bit more of an afterthought.

In the case of Uncharted, if anything, it just feels like more was added rather than diluted when looking at the jump from Uncharted to Uncharted 2. Better single player campaign with an all new multiplayer game. About the same between U2 and U3. Nothing taken away by any means.

I don't think Ascension will have any problems with resource dilution as it looks like it's taking the same multiplayer format that has existed since the old days of multiplayer arcade games. You can play through by yourself, and other players can drop in or out at any given time presumably with the difficulty curve adjusting depending upon the number of players present. How anyone could interpret that as "ruining" the franchise is a bit curious to me.

I would have said the same thing, except in Batman Arkham City there was an online pass that you had to enter to download the Cat Woman part of the single player game. It may have been called something else but it had pretty much the same purpose.

They releasing DLC this summer to clarify.

True, but it serves the same purpose of an online pass. If you buy the game used you miss out on this peice of content that you would have go if you bought the game new.

Yes Sony doesn't do DLC passes yet, but it may for single player only games in the future. It's hard for us to know. I didn't think Sony was going to do online passes either, but they do now.

I'm pretty sure adding multiplayer had nothing to do with how ME3 ended. It's hard to tell why the game ended that way, but I have a feeling Bioward was trying to be the ultimate troll. By doing this they have created so much discussion for the game driving people to go play it to find out why people are upset. Though I may not agree with the ending I do enjoy all of the theories and discussion it has created.

Pretty much similar what I am trying to point out. Developers are  creepin into passes for single player.as well.