Halo finally made the big splash on PC today with the release of The Master Chief Collection on Steam and, if you're into that sort of thing, the Microsoft Store. And in case there was any doubt that PC gamers want it (and want it bad), the collection is currently the number-one selling game on Steam, while the standalone Halo: Reach holds down third place.
As VentureBeat points out, seeing the Master Chief Collection at the top of the Steam charts is a little unexpected because, Halo hype notwithstanding, the games in it—Reach, Combat Evolved, Halo 3, ODST, and Halo 4—are hardly new: The first game in the series came out in 2001, while the most recent, Halo 4, came out in 2012. Most of them haven't been on PC previously, though, and the ones that have ran through the late, wholly unlamented Games for Windows Live, making them effectively unplayable now—if for some reason you happened to be struck with an urge to play an 18-year-old shooter.
The solid start would appear to validate Microsoft's strategy, announced earlier this year, to release more of its games on Steam, rather than keeping them exclusive to the Microsoft Store. Exclusives can boost storefronts—witness the success of the Epic Games Store—but Microsoft's implementation of Universal Windows Apps complicates things for mods, overlays, and other external tools. In fact, while official mod support in Halo: Reach won't be implemented until next year, 343 Industries recently revealed a workaround that will enable players to horse around with mods right away.
Halo: The Master Chief Collection's player count is also skyrocketing: It's currently in 7th place on the Steam Top 100, with more than 60,000 concurrent players, and give that it's only been live for 45 minutes I expect that number will continue to rise. [Update: I was right—six hours later, the concurrent player count is up to 148,000, good enough for third place in the Top 100.] Even though these games are years old, that quick start pretty clearly emphasizes that PC gamers who missed out on them during their Xbox-exclusive days would very much like to get caught up.
Halo: The Master Chief Collection is live now on Steam for $40/£30/€40, or you can go for Halo: Reach by itself (it's currently the only game in the collection that's been released) for $10/£7/€10. It's also available on the Microsoft Store and as part of the Xbox Game Pass for PC.