Crysis in and of itself is a pretty great game with tech and ideas ahead of its time. The main star of the show is the Nanosuit and how it augments your agility, strength, endurance, and a light-bending cloak system that gives you the ability to reenact 90% of the scenes in Predator. What's not to love? Even when the game is at its worst with linearity and vehicles, it's still a game worth playing even today. The GOG version is the best version of Crysis to date, doubly so since it bundles the x64 binaries and doesn't have any outdated DRM. I had Crysis 1 and Warhead on Steam since last year or so but it became increasingly harder to run them both at a reasonable preset, eventually culminating in both stopping working altogether. The GOG verisons of both Crysis 1 and Warhead do not suffer from any of that. Oh and you can use it as a benchmark, that's probably important.
This is a top-down vertical space shooter that has good writing, good soundtrack, an impressive source port, comes with so much guns that it might as well be classified as "Texas: The Game", gives you a multitude of defense options so that you don't die in one hit, has an arcade mode as well as a story mode, as well as support for both manual and automatic saves. And it's free.