Each team has a special weapon, for Terrorist, we have 'ak-47' and for Counter-terrorist we have 'M4A1-S' or 'M4A4'. At the beginning of the match, you don't choose which team you want to be, but you're going to play whit both teams. There are two teams: The Terrorist team and the Counter-Terrorist team, each team has a purpose.
Counter-Strike it's a series of games that are very popular these days even if the first series appeared in 1999.