After tinkering with the game for a few minutes, I found a few settings that could help you increase the game performance.

Click on Esc button. Then click on the third button from the top (Settings). There are two tabs in settings: Controls and Graphics - Sounds

The tab we are interested is Graphics - Sounds tab, from there, the settings from top to bottom is:
Main Volume, Sound Effect Volume, Voice Volume
Windowed Mode, Window Size (Resolution), Show FPS, Graphics Quality, FOV, V-sync
SSAO, Bloom, Depth Of Field, Noise (?), Anti-Aliasing

For the bottom 3 buttons: Back, Preset, Recommended
To optimize the settings:
Slide Graphics Quality to the left, Turn off Noise, Turn off Anti-Aliasing

To my knowledge, the game resolution settings is not usable. The whole game settings will reset to default after quitting the game.

You can set your own *window* size by using this method:
Create a shortcut for the game executable. Right click on the shortcut and click Properties. At the end of the Target textbox, append -screen-width 1366 -screen-height 768 at the back. Change the number to your preferred resolution and click OK.