Team Fortress 2 is a free to play first person shooter, with some whacky and cartoony elements to it. Developed and published by Valve, it is one of their flagship titles, currently holding the title of the second most played game on Steam, after Dota 2.
Even when it was buy to play, the game was absurdly popular and going free to play has only increased it's fanbase. Over the years, the game has enjoyed numerous expansions and updates, but it has never seen anything like what's going to drop on the 15th of August.
Creatively dubbed "Mann vs Machine", this update will add a co-op game mode. A team of six players will have to fight off hordes of robotic invaders, mirroring every class in the game (at least cosmetically). The player team will have to defend one of their Mann. Co. facilities from the AI controlled robot horde that will do anything they can to plant a bomb and destroy it. The monsters will come in waves, each more relentless and difficult than the one before, however, in between these waves, players will have a chance to stock up as well as upgrade their abilities and weapons.
To really make the player(s) feel like they are in a crisis scenario, this will be a true fight between man and machine, the five players will be able to pick anyone from both the BLU and RED teams, to fight, to survive.
The update update will add the previously mentioned gameplay mode, a new map (one of many to come) and countless hours of enjoyment (not to mention some cool robot-themed items that may be added later on, this is a complete speculation from my end).
Mann Vs Machine has a very interesting backstory to it, to shed some light on that, Valve has also released a new trailer as well as a two-part comic.
Once again, the update will be added on the 15th of August and it will be completely free.
The comics can be found here