Marathon Infinity is the third -- and final -- chapter to be released within the popular Bungie trilogy (the same studio behind icons Halo and Destiny). This story began way back in 1999, when it came out for Macintosh operating systems (and, 5 years later was released for Windows). Now it's back, following up on the two previous releases, albeit with some pretty twisted narrative turns including epic flash-forwards and flashbacks.
Thankfully, Bungie freed the code for Marathon Infinity in 1999, which spurred Aleph One being developed -- an open source engine tailored to seamlessly run the Marathon trilogy on modern Macs/PCs using either Mac, Windows or Linux as an OS. Aleph One is also the very engine backing this version of the game. Thanks to its capabilities, you get to enjoy a panoramic view in full HD while playing. Along with some other nice added features, like the option to fully customize your controls, as well as fine tune other adjustments.
The campaign mode in Marathon Infinity is even longer than in Marathon 2: Durandal. But that's not to say that the locations and your enemies are any different this time around, they're very much the same. Once again, you'll pick up a small machine gun as your primary weapon, but overall, you'll be playing a more sprawling, extensive campaign. The story picks up where the previous titles left off, primarily centered around the terminals you find. That said, this time around, you'll be placed within a staggered timeline that zaps you from one place/moment to another in a somewhat convoluted way that'll have you scratching your head if you're not paying close enough attention.
Marathon Infinity is an outstanding shooter. Its graphics -- thanks to Aleph One -- are perfectly streamlined. And, just like the other two games within this saga, the online mode is still perfectly playable, even today. Alas, good luck finding people to actually log on and play it with you though.