How to open the game in fullscreen mode?

Open the game. You will see the main menu that consists of 6 panels. Click the third one (OPTIONS).

Now you should be able to see two panels - click the first one (SETTINGS).

Now you should see four panels - click the first one (VIDEO).

Now two panels should be shown - click the second one (ADVANCED SETTINGS).

Now you shouldn't see panels like before, but many different options. You are interested in the first and second one (SCREEN RESOLUTION and DISPLAY MODE). To choose FULLSCREEN you must click left arrow in the SCREEN RESOLUTION category (to get 1920x1080 px) and right arrow in the DISPLAY MODE category (to get FULLSCREEN).

You have to apply changes by clicking the APPLY option in the lower right corner. You should be able to play the game more comfortably now!