According to post from Blizzard on the Battle.net forums, the new mode is “Designed for those seeking a more serious challenge.” The new mode will allow you to “rank up though a series divisions and tiers in monthly seasons.”
You’ll have to reach level 25 to take on this slightly more hardcore challenge, and the matchmaking will do it’s best to pit teams of similar size against each other.
Game director Jeff Kaplan explained in a new video (posted below) that the progression will go through five tiers, each made of up five divisions (except for the very highest rank, which will only display your actual worldwide rank). The “ladder” in Overwatch makes it so that once you reach a certain tier, you can’t derank from that tier, but you can drop down to a lower division within that tier.
We can also expect Seasons to begin at the first of each month, but the beta will be experimenting with the length of the seasons. Also, rewards will be limited in Competitive Play, as Blizzard want the players within that mode to focus on enjoying the competition itself. Upon it’s launch in the beta, Competitive Play will be barren of any rewards.
Blizzard have also implemented a punishment system for people repeatedly rage quitting from games they’re losing.
“If a player’s game completion percentage falls below our required threshold, they will now receive a warning message (this percentage is calculated based on their 20 most recent games). If that players continues to leave games after receiving this warning, they will incur a 75 per cent XP penalty for future games. This penalty will be removed once the player raises their game completion percentage above our required threshold (again, this percentage is calculated based on their 20 most recent games).”