Here is the full list of all 12 Outland achievements worth 200 gamerscore. It takes around 8-10 hours to unlock all of the achievements on Xbox 360.
Complete any Co-op Challenge Room (General)
Collect 1 000 000 Doubloons (Single Player only)
Complete the full game (Individual)
Defeat any boss without taking damage (General)
Complete any Arcade Chapter below the target time (General)
Collect all Marks of the Gods (Single Player only)
Kill 20 enemies in a row with only 1 health left (Individual)
Smack a bomb so that kills two or more enemies (Individual)
Destroy six enemies with one Beam Shot (Individual)
Collect 10 Marks of the Gods (Single Player only)
Destroy an enemy using a Kamikazer (General)
Destroy a Spider using spikes (General)