NOTE: This guide is for those who can't change the resolution in-game (This is a inssue, a bug, depending on the resolution or graphics card you use. In my case I can't change the resolution above 1600x900 so I made this guide to help others) Thx :)

If you wanna change the in-game resolution to 2560x1440 or 1920x1080

You need to follow this folder:

C:\Users\YOURUSERNAME\AppData\Local\GGST\Saved\Config\WindowsNoEditor


In the folder WindowsNoEditor find the file:

GameUserSettings.ini <-- Open the file using Wordpad.

EDIT THIS LINES:

For 1440p Resolution

ResolutionSizeX=2560
ResolutionSizeY=1440
FullscreenMode=0

For 1080p resolution

ResolutionSizeX=1920
ResolutionSizeY=1080
FullscreenMode=0

+Remember save the file and make it READ ONLY.
+Launch the game.
+Go Settings
+Screen Settings and select the resolution you wanna use. (DONE)

Hope this guide help you!!!
LET'S ROCK!!!

NOTE: Some players have report you can't change the game resolution in settings. That's why I made this guide. In my case I can only play at 1600x900 so I made this guide to help the people with the same issue. Hopefully ArcSystemWork it's working on a patch.