to adjust screen resolution, you need to add/update a line in the config.ini
resolution = one of option values below
with one of these options:
* auto (automatically scales game down to players desktop resolution)
* desktop (sets resolution to players desktop resolution)
* game (sets resolution to game default)
* some resolution value. eg: 1920x1080
Also for the resolution to take effect the player has to restart the game as currently you can not update the resolution while the game is running like most modern games.
Just take a look at my config.ini script found on the vs community wiki via the wiki menu link.