Examine each version of Counter-Strike and you'll find that not a whole lot has changed since the game's inception as a mod for Half-Life back in 2000. Sure, things like hit boxes, recoil, and aesthetics vary between 1.6, Source, and Global Offensive--but the core, minimalistic gunplay remains intact. And that's one of the beautiful things about this hardcore, competitive shooter: It hasn't changed much in over a decade because it doesn't need to, making it one of our top 100 games of all time.
Counter-Strike is brilliant in its Terrorist vs. Counter-Terrorist execution, as each objective-based match comes down to teamwork, strategy, and pure skill. There is no regenerating health. There are no persistent equipment unlocks. If you die during a round, you stay dead until the next begins. Hell, even being dead in Counter-Strike can be intense when you watch the surviving members of your team rush to plant a bomb or rescue a hostage, knowing they're about to walk into an ambush. More importantly, it's usually during death's spectator phase where your teammates will rally and come up with a new strategy for the next round.
The pacing of its matches not only makes for quick games (unless players whip out a tent and camp their own spawn to ambush enemy search parties), but also promotes teamwork in ways few other shooters do. Take Call of Duty: Modern Warfare 3, for example. There, as long as you score high, you unlock Perks, Killstreaks, weapons, and equipment, becoming a more efficient killing machine. As a result, players get obsessed with accruing points, even if that means taking an "every man for himself" approach to team-centric games.
But Counter-Strike is chess with guns, a level playing field where every player is an integral piece on the perfectly balanced board. Though there are some team-specific weapons (such as the Terrorists' powerful AK-47 or the Counter-Terrorists' M4A1), every firearm is so finely tuned that each side has an equally powerful arsenal. Using an assault rifle? You'll need to learn its firing pattern and burst capabilities. If you pick up an AWP--Counter-Strike's infamous one-hit-killing sniper rifle--you better make that shot count, because an enemy could knife you to death by the time your next bullet enters the chamber. This balance makes it so a player with a pistol could be just as deadly as one with a submachine gun. Learning the strengths and weaknesses of each weapon was (and still is) critical to your CS career. The best part? Even if you're an amazing shot, you probably won't last long without some backup, which brings the experience back full circle.
Teamplay blossomed in Counter-Strike's well-designed maps. Admittedly, they weren't all balanced at the start: de_dust was often regarded as a one-sided map that gave Counter-Terrorists the advantage. But as the game evolved, maps like Aztec, Nuke, Office, and Dust2 became the definitive battlegrounds for matches. Every map in Counter-Strike offers a bevy of choke points as well as multiple approaches to any objective, allowing players to plan and execute tons of different strategies. Even years after the game's release, players are finding new ways to take down the opposition.