Here is the full list of all 21 The Aquatic Adventure of the Last Human achievements worth 1,000 gamerscore.
Completed the game.
This time it didn't escape.
You are the strongest human.
Read the story.
Blood and lasers.
Allergic to pollen.
There's an even harder challenge...
Shark attack survivor.
Killed that gross parasite.
This one killed himself actually.
"Could do this with my eyes closed."
You don't seem to know fish have feelings too...
Killed the undead fish.
Octopus is delicious with some potatoes.
Found an alternative use for a chainsaw.
They used their sons to attack you. Not the best fathers...
First boss eliminated. Instantly mastered the uses of the harpoon.
You fully extinguished the human race...
Complete the Boss-rush Mode.
Complete the game without any upgrade crates.
Complete Hardcore mode.