Here is the full list of all 20 ARK BOX Unlimited achievements.
Survive 10 Bossfights
Install all permanent Ark Upgrades
Finish a arcade survival run
Complete all Stages in Free Play and Arcade
Finish a Arcade Bossstage on max speed and difficulty
Download and play 10 new stages
Create 10 complete Stages
Create a stage and share it!
Finish a Stage on the highest difficulty level
Finish a Stage in a max speed Arcade Run
End a stage with 3 active balls
Finish all Free Play Stages
Fire 1000 Bullets with the Ark Blaster
Collect 10 red Zonk Items and loose all size upgrades
Collect 100 Power Ups
Reach the max. Ark size in a Stage
Fire 100 Missiles
Finish a 100 x combo or higher
Destroy 100 incoming enemies
Destroy 1000 Blocks