There's no way to really complete it, but I've put 382 hours into Garry's Mod. The game is just flat out broken, and new patches seem to just introduce more and more bugs that are never fixed. The online game modes are neat, but the communities always suck, the huge amount of free player-made content is cool, but having to wade through all the bad duplicates and pseudo-porn riggings is grueling, and while it's awesome to make your own ragdoll scenes, or obstacle courses and the like by building around maps and adding NPCs into them, Garry's Mod 13 completely screwed over saving (which even before had memory leak issues when you had large saves) - so yeah, no idea why I spent so much time in it for, really, a 6.5/10.