The year is 2027 where most humans are augmented and dwells on sewers for no apparent reason.
You are Jensen, a badass-looking ex-SWAT, where half of his body is augmented but unlike the others he doesn't have a lust for sewers though he visits it occasionally. Unlike most FPSs nowadays which are very linear military-based with mindless action, DX: Human Revolution takes a different approach and gives you the ultimate freedom - you are given numerous paths and ways on how to tackle a mission, either go Rambo or be Snake, it's your choice (minus the boss fights).
People say it still doesn't top the original Deus Ex, I haven't played the original so I can't comment, but compare it to today's games and it easily destroys them in a lot of factors just don'e mention its visuals technically. this path is what the gaming industry should've taken in the place instead of making games with monkey-friendly design.