Counter-Strike is a online FPS (first person shooter) game. It was first released as a mod for Half-Life in 1999 for PC. It is an online only game with no story arc. Players are divided into two teams playing on specific maps with objectives. The maps and objectives are created by the players themselves and hosted on servers dedicated to hosting the game files or on a local machine using virutal private networks.
Objectives are varied and depend on the map in which the game is played. There are three main objective types: hostage rescue, demolition and assassination. Other objectives are made by the communities and includes zombies and paintballing. Zombie mode begins with one player being infected. His objective is to infect other players; survivors aim to prevent the spread. The game continues until the entire game population are infected or the survivors have wiped out the zombies.
What makes this game enjoyable is the variety of tasks and the fact that no two games are the same. There are also four different Counter-Strikes which are all different in their own way; they are run on different game engines which allow a wider variety of mods for each one.