If you want to 100 percent Garry's Mod, there's a catch: you need to play on the same server as Garry himself at least once. That's a lot trickier after two decades, especially since he and Facepunch ...

12. Garry's Mod - Yes, I Am The Real Garry! Achieved by 1.5% of players Around 1.5% of Garry's Mod players have unlocked this achievement, theoretically making it one of the least difficult to get on ...