Here is the full list of all 6 Gladiator Guild Manager: Prologue achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Completed The Bridge arena and finished the Prologue version of the game.
Killed 25 enemy gladiators
Completed the first arena: The Graveyard
Killed 200 enemy gladiators
Killed 750 enemy gladiators
Finished The Game On Hard and Perma Death Mode