Here is the full list of all 46 Squids Odyssey achievements.
Recruit Vesper
Push an enemy in a hole with a shoot attack in mission "Lady in the Water"
Play a mission with the redemption hat
Recruit Sammo
Recruit Clint
Recruit Kapono
Recruit Venus
Recruit Calamary Jane
Recruit Ronimo
Recruit Brad
Recruit Cleef
Recruit Jammer
Recruit Oktoku
Beat the first Guardian
Invoke a mighty kraken
Use 10 miracle tentacles
Hit 6 enemies in one stomp attack
Heal 500 HP with a healer squid
Give a 5 combo melee hit
Defeat 10 enemies in one turn
Defeat 50 enemies on a Seahorse
Defeat 500 enemies
Unlock all seahorses
Unlock all cursed helmets in your inventory
Unlock all helmets in your inventory
Defeat 50 enemies with a jellyfish
Finish mission "back to the wall" in 2 turns
Each squid should bounce on something at each turn in mission "Holding Ground"
Do 10 combos in mission "The Iron Throne"
Finish "The Spirit of the West" in 1 turn without inventory items
Level up a squid to level 10
Level up all squids to level 10
Level up a squid to level 25
Level up all squids from to level 25
Complete Chapter 1
Complete Chapter 2
Complete Chapter 3
Complete Chapter 4
Complete Chapter 5
Complete Chapter 6
Complete Chapter 7
Complete Chapter 8
Get 3 stars for all story missions
Get 3 stars for all bonus missions
Complete all missions in Pro Mode
Recruit Magnus