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