The modding culture is easily one of the best parts of PC gaming, allowing players to install a ton of additional fan-made content for their games that can either tweak some of the game's mechanics... or serve as such a massive overhaul to the title that it ends up revolutionizing the entire experience!
In the case of the latter, there are actually several examples of excellent mods that have gone above and beyond the call of duty to turn a vanilla game into something truly spectacular, impressive... and different. Players who want to experience just how radical some mods can really be should try out the following items on this list. Not only are these mods quite professionally made, but they also end up changing their base games to such a massive extent that one can argue that the genre itself shifts as well!
10 Project Nevada — Fallout: New Vegas
Fallout: New Vegas is considered by many to be the greatest 3D title in the Fallout series, featuring an excellent plot and brilliant role-playing mechanics that truly allow players to get into the shows of The Courier. However, one can't deny that the game hasn't really aged that well, especially when it comes to combat.
However, with the installation of Project Nevada, Fallout: New Vegas turns into a run-and-gun shooter that allows players to enjoy a more action-packed style of gameplay, meaning that one of the biggest problem areas of the title will turn into another positive that will elevate a player's experience.
9 The Nameless Mod — Deus Ex
The original Deus Ex is a spy thrilling featuring a heavy dose of espionage and conspiracy theories. One would expect the mods for this title to not lose the core essence of this title... but these people would be wrong.
The Nameless Mod is easily one of the most ambitious and brilliant mods of all time, doing away with the extremely serious vibes of the original title and paving the way for a more light-hearted and rather meta take into the worlds of meta internet forums, of all things.
8 Call Of Chernobyl — S.T.A.L.K.E.R.: Call Of Pripyat
S.T.A.L.K.E.R.: Call of Pripyat is an excellent title that takes the best — and hardest — parts of a survival shooter and cranks it all the way up to the max, along with a great story that keeps players engaged all the way till the very end.
That being said, players who would rather focus on the exploration side of things can do precisely the same with Call of Chernobyl, a mod that removes all the story bits from the game and adds a bunch of maps in the title as well, including those from the other two games in the series along with a whole host of other content. The game basically turns into a massive sandbox where the player can do anything and everything they want.
7 DayZ — ARMA 2
Most people are familiar with the standalone DayZ, but what they might not be aware of is the fact that this wildly popular title actually originated as a mod from a little-known game called ARMA 2.
A tactical shooter with an emphasis on realism, DayZ turned this gameplay of ARMA over its head into an open-world survival game where players need to scrounge for anything and everything in order to survive. ARMA 2 has been the home for many popular mods that have turned into fully-fledged games, with another such example being the wildly popular battle royale PlayerUnknown's Battlegrounds.
6 Defender Of The Ancients — Warcraft III: Reign of Chaos
Another mod that has transformed into its own standalone product is Defender of the Ancients — an excellent conversion mod for Warcraft III: Reign of Chaos that turns the game into a MOBA.
While RTS elements are definitely rife in DotA, it's the unique integration of some of its mechanics that have helped in the evolution of a completely different genre altogether. Now, DotA 2 stands toe-to-toe with League of Legends as two of the most popular MOBAs of all time.
5 Multiplayer Mod — Just Cause 2
The chaos of the Just Cause series is an absolute blast to play through — quite literally! For the longest time, people could only wonder how the destructive sandbox of Just Cause 2 would play out in a multiplayer setting... until the advent of this mod, that is.
Just Cause 2's multiplayer mod ends up being a chaotic and entertaining romp through an extremely volatile open-world with friends. It's genuinely amazing how the simple integration of multiplayer completely changes the game.
4 The Dark Mod — Doom 3
The original Thief series is easily one of the most groundbreaking and enjoyable immersive sims of all time... but one can't deny that these games definitely show their age right now.
While it might be impossible to play a modernized version of these titles right now, what players can do instead is try out The Dark Mod for Doom 3 — a mod that turns the horror FPS into a stealthy action-adventure that certainly serves an ode to the legacy of the Thief franchise.
3 NeoTokyo — Half-Life 2
The Half-Life titles have been subject to a whole host of mods that have served to overhaul the entire experience, with NeoTokyo being quite notable in this regard due to its eye-catching art style and futuristic setting.
The game plays out in a similar manner to Counter-Strike, with each game being a tightly wound and nerve-wracking experience that never fails to be entertaining.
2 Garry's Mod — Half-Life 2
Of course, it would be impossible to talk about groundbreaking mods for Half-Life 2 without mentioning one particular conversion that turned this critically-acclaimed FPS into a sandbox where players could do pretty much anything and everything they wanted.
The end result was Garry's Mod, a sandbox title with massive potential that has turned into a cult phenomenon of sorts. This mod has now turned into a standalone title that serves as a gateway into a whole bunch of interesting game modes that are extremely entertaining.
1 Counter-Strike — Half-Life
It goes without saying that Counter-Strike is easily one of the most groundbreaking and important mods of all time, serving as an overhaul of Half-Life which has spawned a massively successful and popular franchise.
Counter-Strike's nail-biting tactical gameplay made it an instant hit, and the legacy of this title is proudly being carried by Counter-Strike: Global Offensive.