PlayerUnknown’s Battlegrounds has been one of the biggest surprise hits of 2017, and it has passed a pretty significant sales milestone. The game has sold over 10 million copies on Steam since it went into early access in March.

That’s a pretty big achievement for a title that hasn’t even shipped the final version of the game yet, and is only available on one platform right now. It’s especially impressive when compared to estimates for best-selling games in 2017, like Horizon: Zero Dawn (roughly 3.3 million copies) or The Legend of Zelda: Breath of the Wild (around 4.4 million, counting Wii U and Switch together), which have each sold barely half of PUBG’s 10 million copies in a similar time span. According to one analyst, PUBG is the best-selling single-platform game of 2017 so far.

PUBG hasn’t just hit big sales numbers, though. People are actually playing it, with the game briefly managing to overtake Valve’s own Dota 2 juggernaut for most concurrent players on Steam last month. And with PUBG set to release on Xbox One sometime this fall, it’ll get a whole new audience to continue to grow those numbers further.