Here is the full list of all 20 Abyss Raiders: Uncharted achievements.
Complete the first level.
Fully upgrade all turrets.
Fully upgrade all weapons.
Complete a level without firing a single shot.
Defeat the Stone Guardian.
Defeat the Elder Guardian.
Defeat the Lava King.
Defeat the Abyss Lord.
Collect 100 relics.
Complete uncharted area 1.
Complete uncharted area 2.
Complete uncharted area 3.
Complete uncharted area 4.
Complete uncharted area 5.
Complete uncharted area 6.
In a level, get killed by the last remaining enemy.
Complete a level with very low health.
Complete a level without taking any damage.
Complete a level without using any turrets.
Play a level where there are more than 50 enemies at the same time.