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