Here is the full list of all 30 Astalon: Tears of the Earth achievements.
Completed all entries in the bestiary.
Defeated all the bosses in the Boss Rush mode.
Finished the game with 100% completion.
Explored 100% of the tower's rooms.
Defeated the Black Knight.
Defeated the Gorgon Medusa.
Gathered 100% of the tower's items.
Defeated the Gorgon Solaria.
Completed 80% of the bestiary entries.
Purchased all character specific deals in the shop.
Purchased all of Bram's deals in the shop.
Purchased all of Arias' deals in the shop.
Purchased all of Zeek's deals in the shop.
Unlocked the gorgonslayer Bram.
Completed 50% of the bestiary entries.
Defeated the Gorgon Gemini.
Collected 50000 orbs.
Unlocked the collector Zeek.
Purchased all of Kyuli's deals in the shop.
Purchased all of Algus' deals in the shop.
Killed 1000 monsters.
Collected 10000 orbs.
Completed 20% of the bestiary entries.
Defeated the Gorgon Volantis.
Defeated the Gorgon Tauros.
Found the secret ending.
Reached the top of the tower as the Black Knight.
Defeated the Black Knight as the Gargoyle.
Killed 5000 monsters.
Unlocked all secrets in the game and beat all the unlockable modes.