When I try to start the game, a window pops up and closes immediately. I do not get an error message or anything like that. I tried uninstalling and reinstalling the game without any effect. I even tried uninstalling and reinstalling Microsoft Visual C++ 2008 and 2005.

In the game folder is a "Joshua_Client.log" file:

10/23/16 at 22:24:26
Reading MOD information : SP2
10/23/16 at 22:24:26
SDK Version is : 1.1.0
10/23/16 at 22:24:26
Running Mod : SuperPower 2
10/23/16 at 22:24:26
Mod Version is : 1.5.2
10/23/16 at 22:24:27
Initialize the event manager
10/23/16 at 22:24:27
Initialize the renderer
10/23/16 at 22:24:27
Renderer successfully initialized
10/23/16 at 22:24:27
Initialize the GUI manager
10/23/16 at 22:24:27
GUI Manager successfully initialized
10/23/16 at 22:24:27
Initialize the sound engine (loading/initializing)
10/23/16 at 22:24:27
Initialize the game client (client.dll)
10/23/16 at 22:24:27
###CRITICAL### :
Couldnt load the client DLL
10/23/16 at 22:24:27
#############
FATAL ERROR :
#############
Error initializing joshua, shutting down the engine
10/23/16 at 22:24:27
Disconnection from server complete
10/23/16 at 22:24:27
FPS: 0.000000


How can I fix this?

I would try to reinstall it. You do not try run any mods, correct? All the mods I found on the internet ONLY work with the Steam or Retail version of the game. The GOG version is special.

p.s. also a good thing to do is to remove the "Run as Administrator" GOG puts on nearly all games. And remove any other compatibility settings.

As I already wrote in my first post:
"I tried uninstalling and reinstalling the game without any effect." I uninstalled and reinstalled this game five times now. No mods. It's right after the gog installer tells me that the installation has finished successfully. It doesn't get any more plain vanilla than that. It doesn't matter whether I double click on Launch Superpower2 Link, Joshua.exe or via video_config.exe

I do have a MODS folder containing as SP2 folder though. But this comes directly from the gog installer. There aren't any of those settings on the exe files. So no dice here either. :(

I just installed it again and works out of the box. As you mentioned it installs C++ 2005 and 2008.
There are videos directly at start, can you run the video_config.exe?

Which language did you download? I use English.

I bought this game today and i had this same problem.

after a 2h of searching for solution i find this on steam forum

Selas << my personal hero XD

"
Selas:
thanks, google found this:
the missing thing is vcredist_x86.exe in a newer version, download it here:
(You cannot post any links at this moment.)
"
You can find this on Microsoft
it work for me to.
Just leaving this solution for others