OK on second thought, you probably can skip playing this one. If you have to pay money for it, it isn’t a mod.
So no Counter-Strike or Team Fortress Classic. Quick Disclaimer: This list is only interested in mods, not retail spinoffs. A few of them are super famous, and if it made this list, it’s because I think you should go play it. Valve did a decent job of releasing new content for us all to play, such as Blue Shift and Opposing Force, but the real heroes were the modders who filled the voids with hundreds of standalone fangames of every conceivable length and quality.
Half-Life was a great game, had a huge impact on the shooter genre and everybody who grew up back then loved this game, myself included.
