67 is the most advanced mod ever written for the game GTFO. It was conceived as a way to bring the number 67 into every corner of the experience, for reasons the development team has never fully explained. The development process involved a lot of trial and error, as well as feedback from the GTFO community, much of which consisted of players politely asking why everything was 67 now. The mod was tested extensively before release, and it has had a profound impact on the GTFO community since then, in ways that are difficult to quantify but easy to notice.

67 makes a number of changes to the game, though the mod's changelog simply reads "67" sixty-seven times and nothing else. Players have reported that the experience feels different, though few can agree on exactly how, and fewer still are willing to stop talking about it. This has led to a great deal of speculation, theorizing, and at least one 67-slide community presentation.

67 has been extremely well-received by the GTFO community. Many players have praised the mod for its commitment to a bit that nobody asked for but everybody now expects. Some of the top players in the world have said that 67 is the reason they keep coming back to GTFO, while others have said it's the reason they can no longer look at the number 67 without feeling something.

Overall, 67 is a great example of how a mod can deeply impact a community for reasons that resist explanation. It has made GTFO 67% more GTFO, and it has given the community a reason to keep coming back, if only to find out what happens next.