Note that the advice here is specifically for the original and unmodded game.

  • Deus Ex is a massive game that rewards exploration in many different ways. It's always worth searching areas thoroughly and talking to everyone you encounter for useful pickups, side quests and interesting story bits. Even then, every playthrough is likely to reveal something new.
  • The first section of the game is what turns a lot of people off to it, but once you get past the beginning things quickly get a lot better as the game opens up and you get a lot of cool augmentations to play with.
  • Upgrade Computer to at least "Trained" when starting a new game. You can now hack any and all computer terminals, making the game ten times easier.
  • Manually downgrade Pistols to "Untrained". The unpatched version of the game bumps it back to "Trained" for free, allowing you to spend your initially scarce skill points elsewhere.
  • Focus on Computer, Electronics, Lockpicking and Pistol at the beginning of the game; you should be able to bypass pretty much anything in the first couple of levels with very little fuss. You can then branch out into the other weapon skills based on which weapons you're using.
  • Avoid Swimming and Environmental Training on your first go, as they're of limited usefulness.
  • Utility skills are front-loaded, gun skills are end-loaded. For example, bumping Medicine up to Trained makes every medkit heal an additional 30 hit points whereas further skills bumps only increase the healing by 15 points each despite costing much more. Meanwhile training Rifles (for example) to Master gives you as much of a benefit as the previous Trained and Advanced bonuses combined, not to mention misc bonuses like perfect accuracy on all rifles and being able to snipe cameras.
  • When Paul offers you a choice of weapon at the beginning, it's recommended to take the GEP Gun, as the other two weapons can be found elsewhere in the level and you won't get another GEP gun for a long time. It's useful even outside of combat, as it can easily bust through breakable doors.
  • Deus Ex doesn't really tolerate the run-and-gun approach early on; try to be more methodical when starting out. Use your Riot Prod on individuals and sneak around groups of enemies.
  • When going for close-range non-lethal takedowns with the Baton or the Riot Prod, never aim for the head, as it'll halve their damage. The Riot Prod is always the better option of the two but if you have to use the low-damage Baton, pepper spraying the enemy first with a Pepper gun is recommended, as this'll briefly stun them, which quadruples all damage they take.
  • You can exploit enemy AI by closing doors in front of them. Generally, only panicked civilians can open doors.
  • The silenced pistol is your best friend and perfect for a stealthy approach, especially with accuracy mods or a laser sight.
  • Equipping a laser sight on a gun will immediately set it to 100% accuracy and thus every shot will hit the dot exactly, making all other accuracy bonuses redundant. Having a scope will break this functionality, though.