They're part and parcel of almost every game these days: an open beta. And as important as it is for gamers to get a test, it's also crucial for the developers so they can gauge the performance of their server infrastructure and design.
Perhaps it's because they had months of closed beta beforehand, but the open beta (on PS4 and PC for me at least) held up admirably. And it seems like it held up for millions of others too.
Blizzard's announced via a release that more than 9.7 million players tried Overwatch on all three platforms, with players combining to play more than 37 million matches.
There's not much more to go off, although it provides an interesting point of comparison. EA announced that more than 9.5 million people played the beta for Star Wars: Battlefront, although it seems like Overwatch struck a slightly louder chord.
Battlefront's open beta ran from October 8 to October 13, while Overwatch's open beta ran from May 5 to May 10, although those who pre-ordered early enough could begin playing the game from May 3. (I'm using US times for consistency, incidentally.)
The number that stands out to me between the two games is the number of minutes played: around 4.9 billion minutes of Overwatch were played during the open beta, compared to 1.6 million minutes played for Battlefront.
It's not an indictment of DICE's shooter, of course. Blizzard confirmed over the phone that the figures included the Early Access period as well, so it's entirely possible that more people actually gave Battlefront's open beta a whirl once those figures are discounted.
If you consider how many people ended up purchasing Battlefront — which was more than 14 million, according to EA's latest earnings — it's an indication of the kind of success that Overwatch might have.
And unlike Battlefront, Overwatch doesn't have to worry about launching around the same time as Call of Duty, Assassin's Creed: Syndicate or Fallout 4. (There was Rise of the Tomb Raider as well, but it's doubtful that would have had any effect being an Xbox One exclusive.)