The game is set in an alternative universe's World War II, where the players pilot the newest machines of war - prototype helicopters. In this world, a new and powerful enemy has emerged, threatening to destroy everything in their path.
The gameplay of Under Defeat is fairly typical for a vertical shooter, but with an added twist: players can tilt their vehicles slightly left and right, changing the angle of their fire. This innovative feature allows for more strategy and control over the game's action-packed battles.
Under Defeat was originally released on Naomi arcade machines, and later ported to Dreamcast as one of the last games to be released on the system. The PlayStation 3 and Xbox 360 releases include widescreen HD graphics, as well as original arcade portrait mode.
Under Defeat was released on 1970 .