Earlier this year, Bungie’s 1990s sci-fi shooter, Marathon, came to Steam for free. And Marathon 2 followed in July. But this series is a trilogy. Where’s the third one? I want the thir– oh, it’s here now. Yesterday, the final game, Marathon Infinity trickled onto the storefront, offering a neat little bundle for fans of retro shooters. But it’s also a reminder that we’ve yet to see more of Bungie’s upcoming reboot.