Here is the full list of all 35 Whateverland achievements.
Use Nick's singing to distract Harold
Persuade Harold to give you his cheese
Free Nick by cracking the lock
Make Van fall asleep
Make Zachary and Pip friends again
Fix the vents
Reconcile the sisters
Crack the P. I. G. lock
Make Umaru-san fall asleep
Cook a superb ramen
Cook all the ramen
Make Nick show some moves
Play some decent jazz
Make the date go well
Make the date go okay
Make the date go badly
Tell Ellen she's a great singer
Fix the radiotower
Crack Francois' box
Help Francois get his memory back
Acquire the wisdom of Vitas Varnas
Get the bad ending
Get the good ending
Finish the game
Become Nick's friend
Become Nick's foe
Forgive Nick
Forgiven't Nick
Your actions did matter after all
A click out of one...
Two is binding...
And like that, it's open
Collect every rabbit
Use the magic key
Pet each cat at Clawdia's place