If you've watched streamers on Twitch living out lives as police officers, criminals, or ambulance drivers in Los Santos, you're looking at GTA 5 Roleplay. To join them, you need a tool called FiveM.

There's some steep new competition rising up the ranks on Steam right now, overtaking War Thunder, Deadlock, and even Stardew Valley, and it's probably not what you're expecting. With a 24-hour peak ...