Here is the full list of all 16 Gods of Sand achievements.
Start a new save-game while already having one
Lose the tutorial fight and let your men die
Send a gladiator to a contract
Buy a Ludus upgrade
Change the name of your gladiator
Keep 1000 gold coins
Sell a boss weapon
Defeat Fakir
Defeat Ixionus
Defeat Isis
Defeat Minotaurus
Lose the game
Defeat Amyr
Defeat Herakles
Defeat Nemesis
Defeat the Aberration