Here is the full list of all 38 Okhlos achievements.
Unlock the special ending. No more Monty Python jokes, we promise.
Heal 43 plagues
Have Elektra, Oedipus and Narcissus in the mob at the same time
Beat Hades in under 25 minues
Get a mob with 50 or more phantoms in it
Beat the game without using any items
Unlock all the heroes that took part in that epic and poetic war
Unlock all the heroes that were on board the Argo
Defeat Dyonissus without killing any of his summons
Unlock all the persistent heroes and philosophers in the Agora
Defeat 100 Hecatonchires
Finish a pacifist run
Beat the game with a mob capacity of 30 or less
Defeat the Philosopher God
Defeat all the gods
Finish a world without losing any people.
Unlock the statues of the twelve Olympian gods, and then break them
Defeat Zeus
Defeat Hades
Unlock all the philosophers of Rapahel's painting
Defeat all the subbosses
Destroy 75 or more buildings in one world
Break 55 smoke emitters
Perform 10 perfect blocks in a row
Activate 7 diferent Cryptos
Unlock all the heroes
Unlock all the entries in the encyclopaedia
Unlock one of the secret subbosses
Finish 3 worlds without destroying any buildings
Kill more than 50 enemies in the same level
Finish Lemnos
Finish Athens
Finish Atlantis
Defeat a boss with 5 or less people in the mob.
Finish Sparta
Finish Ephesos
Finish Delphi
This one is on the house. You are gonna have to work for the rest though.