LAS VEGAS—In a flashy hotel on the famous Strip on Saturday night, Andrew “the Annihilator” Ngai ran down an arena walkway with hands in the air, and burst onstage to screaming fans. His two-time world championship was on the line.  

The Australian didn’t know it, but within minutes, victory would seemingly be snatched away from him, all because of a computer glitch. This seems appropriate, since Ngai was playing to be the best at competitive Excel, which is an actual thing.