You can beat this game in a variety of different ways. Lethal or Non-Lethal; Stealth or Combat.
The easiest way to beat the gameplay portions of the game is to go non-lethal on Give Me a Story. To do this I suggest picking the non-lethal option at the start of the game, to get the Tranquilizer Rifle or Stun-gun, which will complement your Takedown ability (tap
). The Tranq Rifle is the more expensive/rare of the two, but it has the shortfall of taking time to affect it's target. Choose which you think is best for you, and then make your way through missions by taking the alternate paths, usually consisting of vents or tunnels in less obvious locations. Check out guides on the "Pacifist" & "Foxiest of the Hounds" Achievement if you want more details and walkthroughs relating to the non-lethal option.
Make sure to save often if you want to redo or undo choices. The best way to prepare you for this is playing Deus Ex: Human Revolution. This game is about 60% the length of Human Rev, and offers pretty much the same challenges, with very little new situational additions.
There is only 1 Boss Fight: The endgame. This is very easy to do if you have an EMP Mine. Place one in Marchenko's path without letting him see you (keep your distance as it will affect you too), and then do a takedown to beat the game. If the lasers and turrets are a problem use vents/cover to sneak around to their terminals to deactivate them.
If this is your first experience, I recommend Give Me Deus Ex Difficulty, as it will allow you to adapt to the needs of the game and make beating the difficulty based achievements a lot easier, as well as prepare you for any future Deus Ex games, or for Human Revolution if you haven't started it yet.