Full list of all 39 Under Defeat HD achievements worth 1,000 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
CLEARED ARCADE MODE IN EASY DIFFICULTY
DESTROYED A SPECIFIC NUMBER OF ENEMIES WITH THE OPTION WEAPON
CLEARED ARCADE MODE IN NORMAL DIFFICULTY
CLEARED THE ARCADE EXTRA MODE
CLEARED STAGE 2-5 IN ARCADE MODE
CLEARED STAGE 2-4 IN ARCADE MODE
CLEARED STAGE 2-3 IN ARCADE MODE
CLEARED STAGE 2-2 IN ARCADE MODE
CLEARED STAGE 2-1 IN ARCADE MODE
ENTERED THE ARCADE EXTRA MODE
CLEARED ARCADE MODE IN HARD DIFFICULTY
CLEARED ARCADE MODE
CLEARED STAGE 1-5 IN ARCADE MODE
CLEARED STAGE 1-4 IN ARCADE MODE
CLEARED STAGE 1-3 IN ARCADE MODE
CLEARED STAGE 1-2 IN ARCADE MODE
EARNED RECOGNITION FOR CONSERVING AMMUNITION
CLEARED STAGE 1-1 IN ARCADE MODE
EARNED RECOGNITION FOR HIGH SCORING SKILL ASSESSMENT
CLEARED NEW ORDER MODE IN EASY DIFFICULTY
CLEARED NEW ORDER MODE IN NORMAL DIFFICULTY
EARNED RECOGNITION FOR HIGH CONTRIBUTION PERCENTAGE
CLEARED THE NEW ORDER EXTRA MODE
CLEARED STAGE 2-5 IN NEW ORDER MODE
CLEARED STAGE 2-4 IN NEW ORDER MODE
CLEARED STAGE 2-3 IN NEW ORDER MODE
CLEARED STAGE 2-2 IN NEW ORDER MODE
CLEARED STAGE 2-1 IN NEW ORDER MODE
ENTERED THE NEW ORDER EXTRA MODE
CLEARED NEW ORDER MODE IN HARD DIFFICULTY
CLEARED NEW ORDER MODE
CLEARED STAGE 1-5 IN NEW ORDER MODE
EARNED RECOGNITION FOR FUEL CONSERVATION
CLEARED STAGE 1-4 IN NEW ORDER MODE
CLEARED STAGE 1-3 IN NEW ORDER MODE
CLEARED STAGE 1-2 IN NEW ORDER MODE
CLEARED STAGE 1-1 IN NEW ORDER MODE
PLACED IN THE LOCAL SCOREBOARD
ENTERED THE MENU SCREEN