Video game mods have been around for decades. The first documented mod was the 1980s rework of Id Software's Castle Wolfenstein, where all Nazi soldiers were replaced by smurfs. Modding has become not only a trend ever since but gave birth to a host of insanely popular standalone games in the process.
The only game type that resists modding since its inception is the slot machine. Starting with Charles Fey's Liberty Bell over a century ago, and up to the massive slot machine library of the Royal Vegas, slot machines have kept the same simple mechanic. There's nothing much to modify on a slot machine, either - just take a look at any number of Royal Vegas slots to see what I mean. The games are built with the same basic functions, on the same principle, which appeals to Royal Vegas players for years. Their themes and bonus features vary, but at their base they are all similar.
This can't be said about the games below, on our list of 5 times gamers outshined game companies
CounterStrike was initially a modification for Half-Life built by gamers Minh Le and Jess Cliffe in 1999. The mod was quite successful, adding the realism and action the game was missing by nature, so it was picked up by Valve in the coming year. Since then, CounterStrike has become one of the most successful online shooters of the world, with several sequels, and massive international competitions organized each year.
Team Fortress was originally a mod for Quake, adding new game modes, classes, and other features to the original shooter. As you might expect, the mod was successful enough to be picked up by Valve. The company turned it into a successful free-to-play standalone game, spawning not only sequels, but video comics and quite a few successful internet memes as well.
Defense of the Ancients was once a simple mod for Wacraft III: Reign of Chaos. Over the years, it has become one of the most successful MOBA (Multiplayer Online Battle Arena) games of our times, being featured in massive international tournaments. League of Legends, a standalone game based on the mod, was inspired by the DotA mod, built with the contribution of one of DotA's original developers.
Day Z was built by gamer and developer Dean "Rocket" Hall for the realistic combat simulator title ARMA 2. Released in 2012, the mod has attracted over one million players in the first six months from its release, and prompted at least 300,000 people to buy ARMA 2. This has determined Bohemia Interactive, the developer behind the ARMA series, to absorb the mod, as well as its developer. A standalone Day Z game is currently under development - it is available as an "early access" game on Steam.
Last, but not least, let's take a look at a game that started out not as a mod per se
, but a remake of the original Half-Life game. Built by Crowbar Collective, a team of developers that constantly changed over the years, the game has rebuilt the original Half-Life from scratch, giving it a new look and feel in the process. The game is currently "early access", with a final release being planned for the second or third quarter of 2017.