Here is the full list of all 20 Headland achievements.
Reach level 20
Thanks for playing!
Found the Northplay offices
Encounter the Tower of ROCKO! Who designed this?!
Dance for a minute in total
What a peculiar robot
Find all Robot Disks
Build every decoration for the Robot Raft
Accept the challenge and beat the Turquoise Gate Arena
Accept the challenge and beat the Gold Gate Arena
Accept the challenge and beat the Purple Gate Arena
Collect all Sword Blueprints
Fully upgrade a sword
Spend 1500 Imagination
Find all Secrets
Took the time out to play a little bit of ball in Patrick's Maze
Spared the Bush Sisters blocking your way
Find the developer slacking off
Beat 200 mean monsters
Imagine all chests at the end of a level