Whoa, what a game. Here's a review from someone who's never played the game before a week ago, and I have to say it's still worthy of all the praise it gets.
+ Biggest plus is the story, still relevant maybe even more so today.
+ Took me over 30 hours to beat on Normal difficulty and only 1 ending.
+ Gameplay. Surpringly smooth platforming and stealth mechanics. Feels good to change playstyles.
+ Best level design in a single player FPS I might have ever seen. Lots of places to explore and secrets to find for an FPS, even by todays standard.
+ Figuring out certain problems actually requires you to use your brain instead of quest arrows pointing the way you have to go and telling you exactly what you have to do.
+ Completing objectives the way you want to feels AWESOME. You really feel satisfied after completing a mission.
+ Even though the graphics have aged, the voice-acting and sound-effects are still great! (explosions are LOUD) A bit quirky and stereotypical at times, but still endearing and engaging. It really grew on me after a while.
- Controls might be too complex if you're not used to old single player games with lots of buttons and menus. I got used to it though.
- Certain sections might be frustrating. Be prepared to die a lot to find out exactly what to do or what path to take for optimal survival.
- The graphics haven't aged great and you need to get used to it before you start to see all the details like what grates you can or can't open, which buttons to push etc. etc.
- Personally not a fan of some of the RPG-elements. You shoot guns as if you're drunk with parkinsons in the early game, which is annoying.
- You might want to play through it in one go because of the crazy storyline, but the game is LONG so you're forced to take your time with this game. Might actually be a good thing though! Expect it to be far easier after your first playthrough though.
So basically Deus Ex is a fantastic game for any one who enjoys single-player, story-driven games and can overlook some of the elements that haven't aged well. There is enough action for any FPS lover so I recommend it to any one who has enjoyed games like Half-Life 2 or the more recent Fallout games. So put this game on your wishlist and buy it ASAP! This truly is one of the classics every video game fanatic should have played at least once!