Beyond all the excesses that might separate Deus Ex from contemporary audiences is a remarkable example of game design.
The player dons the leather trench coat of an agent codenamed JC Denton in the year 2052. JC is an outcast in numerous ways. It is his first day on the job at the UN affiliated UNATCO, where he is among the first agents to receive the physical manipulations of nanotechnology enhancements which offer work effectiveness without making the agent a social oddity (as well as give him an excuse to wear some sweet shades). Ironically, this technology immediately makes him more of an outcast in that he cannot associate with agents without augmentations because they still know he isn't like them as well as the older generation of augmented agents that had to wear their enhancements like scarlet letters. Its an infinitely more creative and refreshing bridge to the player than coming down with another unfortunate case of amnesia.
JC gets thrown right into the fire with his first mission when he must thwart a group of terrorists trying to steal rare canisters of a vaccine for the plague known as the "Gray Death." (However, the player will not feel ill prepared thanks to a training mode that simulates JC's own training and never truly takes you out of the game.) The cases web out into vast conspiracies where allegiances will change and morals will be tested.
Still, there are some finer storytelling tools at work here. The situations escalate at a reasonable pace in order to string the player along to the more epic parts near the end of the game. References to other works (the myth of Icarus, for example) are explored earnestly rather than merely dropped around in a smug fashion. The conspiracies themselves are based on our reality rather than the game's with references to real life conspiracy theories and events. Consider the opening level with the New York City skyline looming in the background. It is conspicuously missing the Twin Towers despite the game being made prior to the 9/11 attacks. The towers were initially omitted because of hardware restrictions and shortly after covered by a back story where terrorists attacked them. It is a "happy accident" for sure, but it is also largely due to a rightful focus on terrorism as a key piece to our political climates even into the future.
Its a shame that there are some blemishes here. In Ion Storm's desire to give a sense of the global nature of the story, they ended up casting a lot of poor voice actors whose performances go well beyond the intended level of pulpy language. Sometimes its not even the fault of the voice actors with awkward dialogue like "The coalition will be fine. I'm not worried about the coalition." and some occasionally heavy handed debates. However, the overall all effect is that the dialogue has the snappiness and cynicism of pulp crime novels ("A forgotten virtue like honesty is worth at least twenty credits.") complimented by more poetic visuals.
The visuals do speak volumes even if the graphics are dated by now (but who is playing a game that is a decade old if they require the shiniest new graphics?). An older engine built for older hardware may initially give the impression that Ion Storm was going for a clean mechanical look due to the obvious limits on the details of textures and the clean geometric look of the stark lighting, but that notion fades fast. Cigarette ad's aimed at children hang over high traffic areas, graffiti covers the back alleys, and flies buzz over the recently deceased. This is a world in decay.
Still, the meat of the gameplay is in the mission objectives. These can be approached in numerous ways. It would be easy to separate every angle into the two neat categories of stealth and open fire but that would be missing the majority of the possibilities, namely everything in between those two ends of the spectrum and then some more options on the side. A player can mix and match on mostly any scenario who they want to kill, who they want to sneak by, who they want to knockout, or whether they want to set traps on normal difficulty modes (there are higher difficulty modes for those seeking a challenge, but open fire becomes less of an option). Manipulation of open ended physics puzzles, conversation trees, and good detective work are occasionally viable as well. The notion of player choice goes further into the game design. Lock picks and multitools (effectively lock picks for objects other than doors) are never intended for any specific obstacle. Rather, the player builds up a supply that they can choose to use at any hurdle but may not have enough for the next one. There is also a choice between a pair of nanotechnology augmentations for each body part and then experience points to spend on skill training. The end result is that the player can tailor the game to their own play style.
The player earns experience points for completing objectives rather than defeating enemies, which in turn puts greater emphasis on the missions themselves rather than the player finding ways to kill as many enemies as possible like in some other games. It also makes stealth an equally viable option to open fire because stealthy players wont be missing any experience points to bolster their characters. And really, leveling the player character plays less of a role in Deus Ex than it does in other role playing games anyway. The handful of skills the player can spend their experience points on are only upgradable up to three thresholds after the default setting of "untrained" (trained, advanced, and master). There are also the prior mentioned nanotechnology augmentations, but those are available for much of the game. Many role playing game developers this generation could take notes on this format in its focus on performing character tasks in the game world (you know, actually role playing) rather than navigating copious menus.
The game play generally feels intertwined with the storytelling, with much of the narrative being conveyed through radio messages to JC in real time. Ambient information of the greater political climate can be found in readable newspaper articles. There is just never a clear divide between what is the developer telling a story and what is action required to fulfill the objective. They are one in the same.
The character JC Denton will eventually follow the same arc no matter who the player is, but the player can still make a few decisions that make the character more relatable. For the majority of the decisions there was one option that was clearly the single one I considered right (yet I'm sure different players would find another option to be clearly right), although this option was fittingly more difficult. How often in the real world is the right thing to do the easiest or even just as easy as the wrong thing? Yet much like its reserved protagonist, the game holds its cards close to its chest and ends with a doozy. It is thought provoking and unsettling. Frankly, I'm still not sure that I made the right choice.