Here is the full list of all 18 Hoa achievements.
Finished the Game
Successfully Navigated through the Reversed Control Section
Discovered Land of the Spirits
Changed the Positions of Robot's Chains 10 Times
Discovered Factory Area
Successfully Navigated the Dark Underwater Tunnels
Discovered Underwater Area
Got through the Dancing Ladybugs
Discovered Tree Top II Area
Got through the Frozen Spiderweb
Got Kicked 10 Times by the Robots
Discovered Underground Area
Jumped on the Back of Frenzy Rhinoceros Beetle
Bounced on Bouncy Larva's Back 10 Times
Discovered Tree Top I Area
Discovered Forest Area
Talk to the First Creature
Watched the Intro Cinematic