Hidden Series 1 Achievements Here is the full list of all 4 Hidden Series 1 achievements.Filter Achievement View View Image viewList view Sort by TrueSteamAchievement desc TrueSteamAchievement asc Achievement name desc Achievement name asc TSA Ratio desc TSA Ratio asc Gamers desc Gamers asc Steam order Date won desc Date won asc What are achievement flags? Click to find outApply Level 10Completed Level 10 Level 20Completed Level 20 Level 30Completed Level 30 CompletedCompleted all the levels