UKRAINE’S WAR has been a forcing house of military innovation. Among the more interesting is the use of “video-game incentives” to increase the armed forces’ efficiency in fighting the Russian invasion. The system ensures that successful drone operators get new drones before their less effective colleagues do. Now the process is being upgraded with what Mykhailo Fedorov, Ukraine’s digital-transformation minister, has called “Amazon for the military”—a scheme that allows units to buy battlefield kit with points won by destroying Russian vehicles and other targets.