Ever wanted to play Revelations 2 in online coop? Like, actual Campaign coop and not only Raid?
As of this week this became a reality and now we can enjoy Revelations 2 with an online friend.

I might update the guide and add pictures soon(tm).

Nothing is perfect and neither is Nvidia's beta software. Recent improvements have fixed a lot of issues.
Known problems are:
-second player loses control and the input is stuck in a loop. Making a new session helps.
-some other games don't have audio. Nothing can be done here.

• A copy of the game.
  
• A PC that is capable of running the game smoothly.
  
• Videocard: GTX 650 or better.
  
• Around 7Mbps upload speed.
  
• A fullscreen DX9 (or above) game.
  
• Xinput capable (Xbox 360) gamepad*.

*You can use third party software like x360ce to emulate a Xinput controller. It works.

• An entry level PC that is capable of decoding 1080p videos.
  
• Around 7 Mbps download speed.
  
• Chrome (browser).
  
• Xinput capable (Xbox 360) gamepad.

First of all, the host will need the latest beta Nvidia Experience and drivers.

• Open Nvidia Experience.
  
• Go to Preferences.
  
• Look down and you'll see "Beta updates".
  
• Put checkmarks on both and press "Check for Updates"(upper left corner).
  
• If you need beta drivers then go to "Drivers" tab and press "Check for Updates"(upper right corner).
  
• Let everything install.
  
• Restart your PC.

If everything goes right from now on when you launch a game you'll see an overlay popup.

• Connect your controller, make sure it works.
  
• Launch the game, be sure to have it running in fullscreen.
  
• Press Alt+Z (default key combination for bringing up overlay).
  
• Click on "Stream".
  
• Click on "Copy Invite URL".
  
• Send this link to your friend (best to do via Steam overlay without minimizing the game).
  
• Click on 'Stream", then "Guest Controls".
  
• Press "Plays alongside me" and then "Done".
  
• Launch any chapter or Raid mode and wait till your friend connects.
  
• As soon as your friend presses "Start" on his gamepad the game will go into local coop mode.

• Plug in your controller.
  
• Ask the host for the URL and copy/paste it in your Chrome browser.
  
• It will ask you to download a plugin, do so.
  
• Press the button to start the stream.
  
• After a while it should load and you'll see the game running with your own overlay.
  
• Select to play and press "Start" on your gamepad when Campaign or Raid lobby is running.

To get your Share function working:

1. Go to Preferences tab.
2. From there be sure that you're in General tab.
3. Put checkmarks on Beta updates (or at least on Experience). This should automatically make it check for updates. If not refer to step 4.
4. Check your version of the software. It should be 2.8.0 or newer (as of Dec 2015). If not press "Check for updates".

When your software is updated be sure to check if your system is compatible with sharing.

1. Go to My Rig tab.
2. From there be sure that you're on Overview (or Share).
3. Here you can see if you system is compatible. If not go to "Share" tab to see what's wrong (likely your card is too old or low tier).

Time to make sure that Share is enabled and overlay is configured.

1. Share is enabled by default. If not enable it. When it's not enabled everything in Share tab (see 3) is greyed out.
2. Go to Preferences tab.
3. From there be sure that you're in Share tab.
4. Here you can adjust your Nvidia overlay. Disable anything you don't need.

Now we're making sure you can access the overlay and have sharing to friends enabled.

1. Go to Preferences tab.
2. From there be sure that you're in Share tab.
3. Be sure that the share to friends is enabled otherwise you won't see the function in overlay.
4. Change the overlay hotkey if needed.

Launch the game (in fullscreen mode).

1. If you see this overlay icon notification then your software is working properly.

My friend's gamepad isn't recognized as player 2 and pressing start has no effect.
Beta software has it's bugs and this is one of them: compatibility. All you can do is restart the game and/or share until it works. The second player should mash the Start button. Usually it takes less than 15 seconds of mashing to make it work. If you're beyond that point you might as well restart.

My gamepad isn't Xinput capable or the button layout/mapping and/or analog axis are messed up. Any way to make this work?
As far as I know this works for hosts only. Download the newest version of x360ce (Revelations 2 is 32-bit), place it in the same folder as game's executable. Launch x360ce, generated xinput DLL and search for your gamepad. Now remap all the buttons, triggers, bumpers and sticks just in case. Close x360ce. With this your gamepad will be recognized as an Xbox 360 one. This won't work for joining players.

Is there any way how I can avoid the whole second player not being recognized issue?
In theory there is one tedious method that I haven't and don't plan to test. For this you'll need 2 gamepads. The host gets software that binds keyboard keys to gamepad buttons. The joining person gets software that binds gamepad buttons to keyboard keys (such as Xpadder). The host sets Share mode to "Play as me". So, in theory, second player presses a button, which translates to a keyboard input. On host's side that keyboard input is translated to a button press. This is all on paper and even I don't believe that this would work, especially the analog sticks.

For how long can we coop?
Quick search says 1 hour. After that reinvite.

Player 2 has some significant delay. What gives?
Your ping is too high. In theory the delay depends on Nvidia servers and then mostly on your internet connection. Not much you can do here.

I'll be updating the guide as I get my hands on any new info about this.
Be sure to report anything interesting or point out typos/mistakes.

Contributors:
X8G7
Eyesfall

Main guinea pig:
Eyesfall