Full list of all 11 HellGunner achievements worth 1,000 gamerscore. It takes around 0.5-1 hour to unlock all of the achievements on Xbox One.
Achievements they've won
Achievements they've not won
Find the hidden box on level 4-2.
Find the hidden box on level 3-1.
Find the hidden box on level 1-4.
Finish the game.
Find the hidden box on level 5-2.
Complete level 5-1.
Complete level 4-1.
Complete level 3-1.
Complete level 2-4
Complete level 2-1.
Complete level 1-1.