Truly remarkable. Gameplay and graphics are the best of it's time, the only thing missing is some DLC.
The graphics of this game are far beyond anything of it's time, and the scenery is a lot like that of Far Cry, now this kind of tropical environment is very standard for most FPS, only this is much more intense and realistic. But be ware, this will demand a lot from you PC. There is possibly a small flaw in the programming, that makes it nearly impossible to play with the highest graphic settings, unless you have the most powerful Processor and GPU on the market. But if you just tone down your graphic settings a tiny bit, i'm positive you will be satisfied with the results.
The NANO-Suite is the true innovation in this game, it simply makes combat more fun, by allowing you to jump higher, run faster, go invisible or become bulletproof for a small time. This will also make the multiplayer part of the game more interesting, since now you no longer die from one shot, so the combat becomes more of a shoot-out scene, the fighting is thereby more intense and feels a bit like playing Unreal Tournament.
Now when you go from fighting North Koreans to fighting Aliens, you'll have to change your combat style a bit, but this is one of the more challenging aspects of the game, and playing in an open-world environment instead of walking a straight line makes it all the more fun.
All-in-all, i don't really have anything bad to say about this game, and it truly is one of, if not THE best shooter EVER.