When a virtually unknown, 14-year-old "Fortnite" competitor playing under the name sF Roller won a solo "Fortnite" Championship Series in May, earning $25,000 and shocking his mother, he had an important announcement to tweet: "thank you aim assist." Aim assist is a feature enabled for players who use controllers -- as opposed to a mouse and a keyboard -- that helps guide the crosshairs toward opponents automatically. It is added to compensate for the fact that aiming with a thumbstick is more difficult than with a mouse, a far more accurate tool. Roller's victory, aided by aim assist, set off a powder keg. After May's tournament, "Fortnite" pros and commentators heaped insults on players who use controllers.