There's been quite a bit of confusion regarding Metal Gear Rising, and the reveal trailer for Metal Gear Rising: Revengeance, which debuted this past Saturday at the VGAs.
The first misconception regarding Rising is that it's a proper Metal Gear game that has a place in the series' timeline. The official Kojipro Twitter account has clarified this notion, stating, "We've only said that the period setting is several years after MGS4. Metal Gear Rising is not part of the Metal Gear Solid series. At present, we can't say more than this."
Additionally, Revegeance is not the same Rising we saw a few years back. That was cancelled late in development, where the basis of the game was allowing you to chop anything. Although the team wanted to complete the game, this basis alone didn't seem sufficient, and it was ultimately cancelled.
Platinum Games felt it was unfortunate that Rising was cancelled, and asked to step in. Kojima then had only one request of Platinum: "a cool Raiden who moves nice and smooth at 60 frames-per-second."
Kojima stated that the original Rising had complex controls and moved in only 30 frames-per-second.
Now, we have an action-packed, sword-wielding, Metal Gear picker-upper Raiden who does move nice and smooth at 60 frames-per-second. And although Revengeance is not part of the official timeline, perhaps it's better that way.