Thunderstrike is a futuristic 3D shooter game released by Millennium Interactive in 1990. The year is 2238 and the most popular sport in the world is the Military Olympics, in which gladiators in various combat aircraft fight robot drones and each other for victory.
The player controls a low-flying combat aircraft in a series of combat arenas filled with enemy robot drones. He starts with the titular "Thunderstrike" fighter by default, but may choose between five different models, all differing in flight characteristics. The player must defend his base installations (red pyramids) from attack by various robot drones; if they are all destroyed the game is lost. Meanwhile he must search and destroy the robot spawn bases (blue/red bunkers); when these are all destroyed the round is won and the player progresses to the next arena.
Source: Wikipedia, "Thunderstrike (video game)," available under the CC-BY-SA License.