This is simply Microsoft’s N-Key rollover test. If you want to see if your keyboard has issues with certain key combinations, use the script below:
The keys you will want to pay the most attention to for gaming are WASD plus any combination. For instance if you are pressing W+A to move forward+left in a game, and want to hit space to jump or CTRL to crouch, it wouldn’t be very good if your keyboard choked on this combination. The above test will tell you if this or any other combo works.
You can also use it to determine the maximum rollover of your keyboard. Most USB keyboards without extra hardware on it will have 6 key rollover, and PS/2 are usually unlimited or “N key rollover”. Some may be anywhere in between – the Razer Blackwidow for instance has 14 key rollover, and the Deck Hassium Pro and Deck Francium Pro both have full N-key rollover when the function is enabled.