When you start a game session on Boosteroid and see a black border around the game image, more likely, your screen resolution is above 1920x1080. Take a look at the example below:
Keep in mind that we support only the following screen resolutions:
What can you do to fix this?
Your browser needs to be scaled up to 150
Right Ctrl + Mouse Wheel Up
Click on the magnifying glass icon in the upper-right corner of the browser
In the end, we receive the following image