Under Defeat HD is a remake of the 2006 G.rev shoot 'em up arcade game, originally released on Dreamcast. On October 27, 2011, G.rev announced a remake titled Under Defeat HD to be released for the Xbox 360, exclusively.
Players assume control of a helicopter, which can be rotated like a more limited version of the mechanism in Zero Gunner 2. Gameplay is largely very traditional, and bears a strong resemblance to some older Toaplan games, especially Twin Cobra. It uses 3D graphics, and a slightly angled perspective to give the game more depth than most other titles in the genre.