• If you're going for the stealth approach spend your skill points in Weapons: Low-Tech. This is the skill needed for most of the quiet weapons.
  
  
• Running low on ammo is never a problem when you use Low-Tech weapons such as the combat knife, baton, or crowbar.
  
  
• You can do more damage to someone if they are unaware of your presence. Sneak in before you attack.
  
  
• Headshots are lethal. Aim for the head when you can, or better yet, sneak up and fire at point blank range. Using the Targeting Aug or Laser Guide mod, or both, makes headshots very easy to do. (Thanks brendan)
  
  
• Use combinations of weapons for best effect. Gas grenades and pepper spray serve only to immobilize your target. Use another weapon to finish them off or just run past them.
  
  
• The art of stealth takes practice. Its a combination of walking, and avoiding the line of sight of your target. Imagine a 180 degree arc spanning the left and right shoulders of a person in the direction they face. As long as you walk outside of that arc it doesn't matter if your 20 feet or 2 feet away, they will never know you're there. Being inside that vision arc can be done safely if you duck behind something.
  
  
• Some doors can be blown open using explosives. But why waste a LAM if a crate of TNT is close at hand. Just carry it over, crouch when you drop it, then detonate with your pistol.
  
  
• TNT crates, LAMs, and missiles when detonated near trip sensors (security beams) will destroy them without setting off any alarms. Missiles also do a great job on cameras.
  
  
• Never toss a TNT crate to the ground without crouching first. Either that, or make sure you have a good throwing arm.
  
  
• If you find someone you can converse with, always try it more than once. Many conversations can be extended by highlighting the person and pressing your use button (default: right-mouse button). Key pieces of information are not always revealed in the first conversation.
  
  
• Guards have patterns. When attacked some will immediately run for an alarm switch ignoring all else around them. Other guards will persue you but after taking a certain amount of damage they too will run away ignoring everything. When guards run away from you take advantage of it by closing the distance to get better shots. Don't worry, they won't fire back.
  
  
• Its actually better to crouch and run than to stand and walk. Crouch running makes less noise and you move faster than standing and walking. Strange, but true. Even makes handling heavy weapons easier when you lack skills.
  
  
• Bots are dumb. They have to see you for detection purposes. Some are deaf but later in the game they can hear you if you are close enough. Even the bigs ones.
  
  
• Just one upgrade of computer skills lets you hack. Not enough to read everyone's email, but it will due for disabling security, opening doors, and gaining access to many good things like ATMs.
  
  
• The spy drone aug has a nice bonus. If you get close enough to a door, the drone can be materialized on the other side. (Thanks to Col. for the tip.)
  
  
• With the Dragon's Tooth sword and a maxed out Combat Strength aug, its possible to smash open locked doors provided the door strength is not invincible. (Secret hand sign to Zippy the Clown.) More research revealed that even a maxed out Weapons: Low-Tech or at least advance level Low-Tech also enables the sword to smash things without the need for the Combat Strength aug. However, when both the aug and the weapons skill are maxed out, you can smash alarm switches and cameras without setting off the guards.
  
  
• For those trying to make it through the game with a low body count, note that unless the guards next patrol point is to his right, the guard will always spin to the left when moving to the next part of his patrol. (Thanks to JkJames for the tip.)
  
  
• Use the spydrone aug to disable cameras, and eletrical systems with its EMP pulse. Even better, it can disable LAMS and other proximity place grenades. (Thanks to James for the tip.)
  
  
• Using the StrengthAug, you can build barricades across openings blocking would be attackers. (Thanks to Peter for the info.) Or, just try pushing stuff around. Even small crates can do the job but don't push it. The enemy can hit you through even the tiniest of cracks. (Conspiratorial nod to Nick for the tip.)
  
  
• Doors, lockers or whatever that have a strength of 25% can be opened using regular darts off the mini-crossbow. After destroying the door you can usually reclaim the dart. (Thank you James for the info.) Other weapons and also break apart low strength doors. A door of 10% strength can be shattered by just about anything.
  
  
• Sabot rounds, used in the shotguns, can destroy cameras and alarm switches when shot enough. (Thanks Philip.)
  
  
• Though I don't find it useful, I've received many emails that the Dragon's Tooth Sword makes a nice infinite light source.
  
  
• Wait for your crosshairs to come together before zooming, it reduces the amount of shaky hand. (Thanks Dustin.)
  
  
• Stick a grenade on the wall. Jump onto it. Place another. Jump onto it then reclaim the previous. Repeat until you have scaled the wall.
  
  
• Even if you already have the weapon, picking up another duplicates an ammo clip. Additionally, its an extra clip of whatever you had loaded in your weapon at the time. (Thanks El Sabotender.)
  
  
• Mastering your skills in rifle makes the sniper rifle a tool for destroying cameras, turrets, alarm switches, and doors with 50% strength or less. (Thanks Frank.)
  
  
• Using non-lethal means of taking out a MiB or WiB not only avoids the ugly detonation, but also gives you a body that can be searched for goods. (Thanks Aiee)
  
  
• Using the GEP Gun / Assault Shotgun Sabot round combo helps to conserve your ammunition. One GEP shot weakens even the biggest bots enough that a one or two sabot rounds will finish it off. Alternately, use only the sabot rounds on small bots. (Thanks Khadgar)
  
  
• Standing under a camera before it sees you is the best place to hide from it.
  
  
• Standing under a turret prevents it from shooting you.
  
  
• Sometimes its better to leave a camera active. If its near a turret reprogram it. Set the camera off and watch the turret make quick work of the guards. (Thanks Velochy)
  
  
• The Aggressive Defense System does more than just missles. It can also protect you from the flamethrower and plasmagun. Be warned, at close range it can't protect you.
  
  
• For those of you playing multiplayer (or even singleplayer) consider editing your user.ini file (make a backup copy first) and do something like this:
  
  Tilde=ActivateAugmentation 0|ActivateAugmentation 1|ActivateAugmentation 7
  
  What this will do is connect all three augmentations to the ~ (tilde) key. Now, obviously there are better keys that can be used but imagine being able to combine your augmentions in groups. Now you can activate several augs at once with one key press. (A big thanks to Lee for this tip)
  
  
• Though this is more of a cheat I've had too many emails to ignore this. When you use either a lockpick or multitool pull up your inventory immediately after you start. Wait anywhere from 5 to 20 seconds and then escape back to the game. Whatever keypad or lock you were working on should now be open even if you needed more than one lock lockpick or multitool. This works irregardless of skill levels.
  

Copy the shortcut for Deus Ex. Modify the target line from this:

C:\Games\DeusEx\System\DeusEx.exe

to this:

C:\Games\DeusEx\System\DeusEx.exe -hax0r

This enables the cheat codes. Next, make a backup copy of the user.ini folder in the Deus Ex\System folder. Open the file in a text editor (careful when using WordPad to save as Text and not Word 6.0 format or RTF format) and find both instances of:

Tilde=

Change them to:

Tilde=Say

Alternately with the latest patch adding multiplayer you can opt to just press the talk key ('T'), press backspace to remove the 'say' part from the line and enter the cheat codes that way.

Visit Gamespy's CheatingPlanet for a list of the Deus Ex Cheat Codes. You don't have to do the set DeusEx.JCDentonMale bCheatsEnabled true command, that's what adding -hax0r to the shortcut does. Mac users will have to do this or modify the user.ini as the CheatingPlanet Deus Ex page suggests since a Mac alias doesn't like to be fiddled. Access to the command line options on the Mac Deus Ex program is done my holding down the option key while double-clicking the app. Adding -hax0r may enable cheats from here.

One cheat you might not find mentioned is this one:

set jcdentonmale skillpointsavail xxxx

Replace xxxx with four digit number. This will set your current skill points to whatever number you've put in. (Thanks Paul)