From Sega Retro
Under Defeat (アンダーディフィート) is a military themed shoot-'em-up developed and published by G.rev, and released exclusively in Japan. It was originally released on October 30, 2005 for the Sega NAOMI GD-ROM arcade platform, with the Sega Dreamcast port arriving on March 23, 2006. In February 2012 the game was ported to other formats as Under Defeat HD.
In Under Defeat, one or two players control a helicopter through five (generally) vertically scrolling stages. Each stage has a range of military themed enemies, including tanks, gunships and other helicopters, as well as an end of level boss. To encourage risky play for high reward, bosses are harder and yield more points when a player has fewer lives left. Once the player has completed the five stages, the game starts a second loop on stage 2-1, a mirrored version of stage 1-1 with an increased difficulty level and altered background. Once stage 2-5 has been completed, the game is over.
Only two main weapons are controlled by the player: a regular vulcan shot with unlimited ammunition, and a limited number of screen-clearing bombs which can be added to with pick-ups. The player is able to adjust the helicopter's angle by releasing the fire button, to enable diagonal shooting. In addition to the helicopter's main weaponry, the player is able to spawn an "option" drone by releasing the fire button until the option bar has charged completely, and then pressing it again. Use of the option drone is only limited by recharging.
The option is capable of using three different weapons, selectable through pick-ups. The yellow vulcan shot is quickest to charge and allows the drone a high level of autonomy, but is weak. The green cannon fires eight medium powered shots, with more limited target finding. The blue rocket grenade is an extremely powerful single shot attack that also causes blast radius damage, but has almost no target-finding capability and is the slowest to charge. Point scoring is dependent on effective use of option drones, as enemies detroyed by the option score twice as many points. Additionally, picking up the item for your current weapon results in no change, but a 5000 point bonus.
Under Defeat was made available in three editions. The regular edition contained the game alone, while the limited edition featured an alternate cover and an arranged soundtrack CD as a bonus item. Players who pre-ordered the limited edition from the Sega Direct web store also received a sticker and a poster.
During the game's pre-launch marketing, it was announced that Under Defeat would be the final game released for the Sega Dreamcast. This claim was repeated on the back of the game's packaging. However, Milestone Inc. confirmed that it had plans to release another Dreamcast game, and had contacted Sega in order to ensure that this would be possible. Eventually, two more games would be released: Trigger Heart Exelica, by Warashi, and Karous, by Milestone.