When I start Dex, the main menu and music appears for about 1 second, the exits to the desktop without error message.

In the log file under Dex_Data\output_log.txt I found these lines.

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Crash!!!
21:48:36 GOG error: Galaxy.Api.GalaxyInstance+RuntimeError: Could not start GalaxyService
at Galaxy.Api.GalaxyInstance.Init (System.String clientID, System.String clientSecret) [0x00000] in <filename unknown>:0
at GogStats.Start () [0x00000] in <filename unknown>:0

(Filename: C:/buildslave/unity/build/artifacts/generated/common/runtime/UnityEngineDebugBindings.gen.cpp Line: 64)

SymInit: Symbol-SearchPath: '.;C:\Dex;C:\Dex;C:\Windows;C:\Windows\system32;SRV*C:\websymbols*http://msdl.microsoft.com/download/symbols;', symOptions: 530, UserName: 'Test'
OS-Version: 6.1.7601 (Service Pack 1) 0x100-0x1
RuntimeError: Could not start GalaxyService
at Galaxy.Api.IAuthListener..ctor () [0x00000] in <filename unknown>:0
at GogStats+AuthListener..ctor () [0x00000] in <filename unknown>:0
at GogStats.Start () [0x00000] in <filename unknown>:0

(Filename: Line: -1)
-------------------------------------------------------------------------------------------------------------- --------------------------

I don't have GOG Galaxy installed. I figured out this happens when I deny internet access to Dex.exe via my firewall. If I allow the access via firewall, but internet connection is not available, it works.

I could also fix it by deleting these files:
Galaxy.dll
GalaxyCSharp.dll
GalaxyCSharpGlue.dll
GogGalaxyHooks.dll

It would be nice I can play the game without allowing internet access.