Here is the full list of all 84 Ostrich Island achievements.
You activated Eggs Converter.
You found Statuette of Bathilda, sister of Ostrich.
You unlocked Jumper ability.
You found the skin: Cow
You found the skin: Chicken
You found Statuette of Alarice, aunt of Ostrich.
You activated all portals on Island 4.
You found Statuette of Osrik, uncle of Ostrich.
You found the Hat of Sea Dog.
You found the skin: Tiger
You found Statuette of Dedrik, grandpa of Ostrich.
You collected the third Egg in a split second.
You collected two eggs in the blink of an eye.
You unlocked Fast Walker ability.
You unlocked Egg Master skill.
You unlocked Sharp Vision ability.
You found the Treasure Island.
You mastered Co-op mode and finished with higher score several times.
You found the Elegant Hat.
You found Statuette of Manfred, nephew of Ostrich.
You found the skin: Zebra
You haven't seen such an Egg before.
You found the White Hat.
You found the skin: Striped
You found the Sunglasses.
You found Statuette of Egbert, brother of Ostrich.
You found the skin: Lizard
You found the Green Hat.
You completed the first island.
You have collected all eggs on some island.
You found Statuette of Dagna, niece of Ostrich.
You found the skin: Domino
You found the Photo Camera.
You found a hidden bonus on the first island.
You caught all the fish on the second island.
You collected all available bonuses on Tiny Island.
You destroyed an idol without using a super power.
You solved the tree puzzle on the first island.
You lowered a bridge without hitting it.
You fixed the broken portal before having fun.
You unraveled the destiny of Giant Egg.
You do like to play dirty, don't you?
You found a fish in a mud!
You destroyed over 50 trees on some island!
You found all the hidden food on island six.
You caught 7 butterflies.
You have finished the game.
You survived on the cloud #11 for 5 minutes.
You scored a goal while playing with mangos!
You found the location of Labyrinth.
You found Statuette of Agmund, cousin of Ostrich.
You found Statuette of Morgen, father of Ostrich.
You found Statuette of Alda, mother of Ostrich.
You found a beautiful doll.
You found the Santa's Hat.
You found the Cowboy Hat!
You found the Peaked Cap.
You found the Strange Hat.
You found the Cork Hat
You found the Bowler Hat
It's Halloween Time!
You found the Heart-Shaped Glasses.
You found the skin: Black & White
You found the skin: Cheetah
You found the skin: Bamboo
You took 50 photos.
You are the King!
You unlocked Heavy Hitter ability.
You unlocked Score Collector ability.
You unlocked Sprinter skill.
You unlocked Brawler skill.
You increased Eggs Converter Speed.
You increased Eggs Converter efficiency.
You installed Water Control Device.
You joined Workshop, created a skin and gifted it to Ostrich Island Community.
You finished the Game+ mode.
You completed the collection of beautiful Ostrich Island photos.
You reached 50% mark on the way to the game mastery.
You have discovered every nook and cranny of Ostrich Island. You are the Master of this game.
You discovered The City Of Lost Chickens!
You destroyed a small army of bony fiends by dropping a tree on it.
You walked on a beach with at least 3 chicks.
You sent home two chickens at once.
You have scored a goal with a lobster. Birds gonna get angry.