Just a quick update to let you know that Metal Gear Rising: Revengeance is now available to download on Steam and is priced on PC at £19.99. The newly released version includes all three DLC missions, and brings in a couple of changes (you can, for example, now access cutscenes in the menu and tweak graphic options).
It's also worth noting that the game is currently not playable in off-line mode, as was confirmed in a Tweet from Konami: "We are aware of the offline play issue for Metal Gear Rising for Steam and are working on a fix. Please stay tuned for more updates!"