You start out as JC Denton, an nano-augmented UNATCO agent, meeting up with his brother Paul before the mission starts. The NSF is a terrorist group that has hijacked a shipment of Ambrosia (a cure for the Gray Death virus). You later learn that your brother has defected to NSF, because UNATCO made the virus and is using it to keep control.
Sounds simple enough. The game isn't a simple shoot and kill one, I guess you can say it's a mix of FPS and RPG. It all depends on how you want to play. Want to go in and shoot? Go ahead. Want to be stealthy? Sure. Kill everyone or be merciful? Whatever you want. The world is quite open.
Also conversation with NPCs are very important. You can choose what you want to say. Some answers may be more favourable than others. But that's the fun of it.
As I said, you're a nano-augmented agent. This means you've got several ways of upgrading yourself by using augment canisters. Your entire body can be augmented, and every part has TWO options to choose from. For example:
You get a canister which will augment your feet. You've got two options: Run Silently or Run faster. You can only choose one, so pick carefully.
Once you've got an augmentation, you can put skill points into it. Say you got Vision Enhancement. First upgrade will get you Night Vision, next upgrade will get you Infravision and the next upgrade will make it so you can see through walls.
Apart from that there is a HUGE arsenal of various weapons, both lethal as non-lethal, which come with their own upgrades. Reducing recoil, larger clip, etc. You can also hack computers, so that the camera systems won't work. or even turn turrets on your enemies. Also pick a lock to get into a base, the options are limitless.
As far as guns and inventory go. You have to pick and choose carefully. This isn't just 'grab the gun and go', you have to make sure you've got space to keep the gun. More often than not, you'll have to leave behind some cool weapons, because there simply isn't enough space. Or you have to sacrifice some gun for that cool flamethrower.
What I think is pretty awesome now, and back in the day didn't even think about is the fact you can read books. Of course, not the entire book, but bits and pieces of newspapers or a book. it would provide an interesting perspective. Literary works are reference quite a lot actually. It made it more interesting when I replay the game.
The replay value of the game is rather high. You can approach a mission a different way, and you have different endings: three in fact. But that you will have to discover yourself.
Deus Ex is a rather 'old' game by today's standards. The graphics are pretty laughable when you compare it to others. The game was released in 2000 for pc and Mac, and in 2002 it was released for PS2, with that came updated graphics. I wouldn't mind it if they do that for pc as well.