About
Overwatch is an upcoming multiplayer first-person shooter in development by Blizzard Entertainment. Unveiled at BlizzCon 2014, the game emphasizes cooperative gameplay using a cast of various "heroes", each with their own abilities and roles within a team. The game entered closed beta in North America and Europe on October 27, 2015, with plans to bring the beta to Asia at a later date. The final closed beta weekend began on April 15, 2016 and primarily served as a stress test for Overwatch's servers, lasting 36 hours. The game is scheduled to be released on May 24, 2016, for Microsoft Windows, PlayStation 4, and Xbox One.Gameplay
Game modes
Overwatch currently has four main game modes, including a hybrid of assault and escort:Assault: The attacking team is tasked with capturing two target points on the map, while the defending team must stop them.
Escort: The attacking team is tasked with escorting a payload to a certain delivery point before time runs out, while the defending team must stop them. The payload vehicle moves along a fixed track when any player on the attacking team is close to it.
Assault/Escort: The attacking team has to capture the payload and escort it to its destination, while the defending team tries to hold them back.
Control: Each team tries to capture and maintain a common control point until their capture percentage reaches 100%. This game mode is played in a best-of-three format.
Characters
Characters in Overwatch come in four varieties: Offense, Defense, Tank, and Support. These roles serve to categorize the heroes of Overwatch by similar characteristics that can be used to describe them and their playstyle. The first appearance of an Overwatch character in a released game was on April 19, 2016 in Heroes of the Storm.Offense: Offense characters have high mobility and are known for their ability to deal large amounts of damage. To balance this, offense characters have a low number of hit points.
Defense: Defense characters excel at protecting specific locations and creating choke points. They can also provide several means of field support, such as sentry set-up and trapping the enemy team.
Tank: Tank characters have the most hit points out of all the characters in the game. Because of this, they are able to draw enemy fire away from their teammates to themselves, so as to disrupt the enemy team.
Support: Support characters are utility characters that have abilities that enhance their own team and/or weaken the enemy team. They might not deal the most damage or have the most hit points, but the buffs and debuffs they provide ensure that their teammates who do will make short work of their opponents.
Links:

1. Download the generator from the link above.
2. Un-zip the files.
3. Start Overwatch_Gen.exe
4. Press GENERATE .
5. Copy the code and go to : Official Website.
6. Login / Create an account if you don't have one.
7. Go to my account and Apply Code
8. Enjoy! :)
Source:Wikipedia