Here is the full list of all 30 Apotheon achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Beat game on Olympian Difficulty
Find all lockboxes on Olympus.
Acquire the powers from all twelve Olympian Gods.
Acquire the Thunderbolt of Zeus
Find all rare weapons on Olympus.
Acquire the Crest of Ares
Acquire the Aegis of Athena
Aquire the Sandals of Hermes.
Acquire the Trident of Poseidon
Access the sunken wreck of the Euphemia in the Sea.
Access the Gold Mine in the Sea.
Aquire the Cestus of Aphrodite.
Aquire the Kantharos of Dionysus.
Aquire the Artifice of Hephaestus.
Meet the Necromancer in Hades.
Access the Hunter's Trove in the Forest.
Access the Secret Grove at the Shrine of the Nymphs.
Access the Refugee stash in the Forest.
Access the Assassin Stash in the Swamps.
Access the Symposium of the Sun in Apollo's hall.
Access the Agora Market Scroll-keeper’s Office.
Access the Agora Armoury.
Access Apollo's nectar cellar.
Root out the assassins in the Acropolis.
Access the Merchant Stockpile in the Acropolis.
Access Kleio's gift in the Acropolis.
Acquire the Lyre of Apollo
Acquire the Sheaf of Demeter
Acquire the Bow of Artemis
Ascend to Mount Olympus