I have a few suggestions to make multi-monitor gaming more enjoyable in this great game. I didn't see any posts containing Eyefinity or Nvidia Surround pertaining to these issues.
Listed in order from most important (game breaking or strongly affects game play), to cosmetic (would be a big plus, but not critical). I'll update this post if I notice anything else. Currently there was only 1 important issue, and one very minor issue.
1) Damage indicators. at ultra wide resolutions, they only sometimes appear on the screen, and not anywhere useful. When I have seen them, they are arranged in a circle, and move around as I look around.
Here you can see them on the left side of the image. If I were to look right, then they would move off the left side of the screen, and depending on the gun appear on the right side. But most of the time they do not appear anywhere.
2) Centered HUD elements. Right now, Chat and kill messages are on the far left of the selected resolution, and the Ammo counter is on the far right. Since these are in the peripheral vision, it is difficult to catch critical information.
Generally, multimonitor games center the HUD on the center monitor, or allow you to move HUD elements around.
The 2 I have listed above are usually just simple config file tweaks to get the HUD elements in the proper positions. I'm not familiar with the UNITY engine so I'm not sure if they can be done client side at this time.
HERE is a link to the WidescreenGamingForum(WSGF) thread on Guns of Icarus Online.
Now for the good. The game is HOR+, that is great news and makes the game very playable on multimonitor gaming. The menus and game lobby are scaled and centered and not stretched. This is awesome. I am glad that some elements of the game work perfectly on multimonitors. The HUD elements scale properly, and are not stretched, they just need to be repositioned.