Skill at Time Achievements Here is the full list of all 4 Skill at Time 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 Winner!Complete the game Zombie slayer!Kill 50 zombie Red zombie slayer!Kill 50 red zombie Copters destroyer!Shoot down 50 copters