Like most Valve games, there are plenty of ways in which anyone can experience in Left 4 Dead 2. There is a very large modding community for this game, that is also supported by Steam themselves. The changes can be as simple as cosmetics of the special infected, to improving the A.I. of the bots so they can use more weapons and respond more quickly to people who are downed.
The interactions of the game are quite simple and straightforward. For example, changing from your main weapon to your side weapon only by pressing one button (y for the Xbox). Healing with a first-aid kit only takes 2 buttons (right on the d-pad, then holding down right trigger for the Xbox). Crescendo events, such as finales, forcing the player to strategize by placing Jerry cans and gas cans in locations, using mounted machine guns and healing up. The A.I. director can also have an impact, as it can directly alter the map depending on how the players interact. For example, in the campaign, Dead Center, level 3 The Mall, there is a crescendo event where players activate an alarm and must turn it off. There are two methods: either through breaking a store window or opening an emergency door.
Playing Left 4 Dead 2 online forces players to connect and work with other people as a team. The Charger, Jockey, Hunter, and the Smoker all pin survivors when they use their main attack. Players must therefore work together when they play as survivors or the special infected, to beat the other team. It could mean staying together and helping picking up downed survivors, or it could mean leaving the others behind so that you can carry on and try to win for your team.
Left 4 Dead 2 mixes the use of words and sounds in the game to help the survivors while also explaining the story. Graffiti is often found inside the safe room’s: messages to loved ones to meet a location or warnings about an evacuation center being overrun by the infected are just some of the graffiti in the game. The special infected may also have musical cues in game to tell the players what they will face soon. The most well-known of these is the Tank’s theme, which instantly captures people’s attention and everyone loses their shit as they try to find it before it kills them.
As far interpreting this game, there is a vague sense of hope for humanity in the game. There millions of people infected in the world, but there are a couple of survivors out there helping others and there may be a future for humans after all. The game could very well be a simple zombie shooter, but it could be read about a tale of the human spirit and desire to survive in any situation.