Building a prequel to one of the most critically acclaimed PC games of all time is no easy task. Over the course of the past four years, the team at Eidos Montreal has been doing just that, however, and it looks like all of its efforts are about to pay off. Deus Ex: Human Revolution is here, and like its namesake, it may just be one of the hallmark titles of its decade.

As gamers, we've become used to categorizing games into genres, not by their themes, but rather based on how they play. Deus Ex: Human Revolution breaks out of that mold because how you play is determined solely by the individual. Two players can experience totally different things, simply because they choose to do different things. For one player, Deus Ex: Human Revolution is a stealth-espionage game, while for another, it may be a duck-and-cover shooter. Seamlessly mixing these genres is no easy task, but Deus Ex: Human Revolution does it in stride.

Perhaps the best example of the game's flexibility came at the end of our visit to Eidos Montreal two weeks ago. After finishing dinner, the PR folk came around and asked everyone which parts of the game they had seen to ensure no spoilers leaked out. Among the 15 or so press members in attendance, each person had seen something different.

This flexibility in gameplay was backed up by our own experience with Deus Ex: Human Revolution. After playing through on the quick path, we went back and started over, giving it a go with different choices, exploring new areas and trying new strategies. Much like Alice venturing into Wonderland, we were quickly enthralled with seeing exactly how deep the rabbit hole went.

The magic of Deus Ex: Human Revolution is that every single choice in the game feels organic. While the main quests and side-quests are called out in the game's HUD, you are free to ignore the side-quests. Some of the side-quests are presented to you directly, while others you have to come across in the world at large. Even completing said quests is at your discretion, with the game giving you the option to lie to the quest givers and hold back certain items for yourself.

Flexibility in gameplay wouldn't work if the underlying mechanics weren't solid, but that's not a worry here. Although the Xbox 360 controller does feel a bit crowded from time to time (a few more buttons would have been nice), the game always felt responsive and rock solid in terms of control. The cover system is naturally integrated, allowing you to use just about any large item as cover.

No matter if you are taking the stealth angle or the more "direct" approach, cover is inherently useful. Even as an augmented transhuman, bullets still hurt, and you can't take more than a few before going down. Be smart about how you use your environment, and it's possible to get through pretty much any area in the game without suffering so much as a scratch.

Level design also deserves quite a bit of kudos because the team at Eidos Montreal didn't build "levels" in the traditional sense. They have instead built wide-open areas in which missions simply happen to occur. How you progress through an area to your objective is completely up to you.

For example, in one early section you have to make your way through a gang banger hideout in the slums. You can sneak in through the sewers. You can fight your way in through the main entrance. You can climb up the building next door and punch your way through a wall (assuming you have the appropriate augmentation). Those are just the paths we found. Just like the real world, areas within Deus Ex: Human Revolution are quite porous; it's up to you to search out all the hidden nooks and crannies.

While personal play style has the most direct impact on how you approach the game, how you develop your augmentations also has a lot to do with it. No matter what you do, it is impossible to unlock every single augmentation skill in the game. According to the developers, even a great player can only unlock up to 75 percent of them in a single play through. This means that certain areas may be available (or unavailable) to you, and certain skills, such as hacking, may be more or less difficult, all depending on how you develop your character.

Those who spend the time searching high and low are rewarded both with weapons (there are plenty of hidden stashes throughout) as well as with story bits. The plot driving Deus Ex: Human Revolution is a lot more complex than initially hinted, and the only way to really know what's going on is to spend the time talking to people, searching out eBooks and hacking your way into various personal computers to read e-mail. E-mail can sometimes contain useful passwords (granting you access to yet other systems), but it is typically there to flesh out the game's backstory and offer insight into the grand conspiracy pushing forward the plot.

Hacking a system is handled via an engrossing little minigame that balances risk and reward. You have to make your way down a virtual circuit and claim the end point before the system's security software boots you out. If you're fast enough, you can even claim bonus goodies. Increasing your hacking augmentation makes it less likely you'll be noticed by the security software, but the rest of the minigame remains the same.

Like many other games, Deus Ex: Human Revolution features some impressive boss battles, where you'll have to get your hands dirty and make use of all the nifty toys you've collected along the way. No doubt about it, the boss fights are rewarding; however, the real "boss fights" aren't the ones in which you use weapons, but rather your mind.

Scattered throughout the game are conversation points with various characters in which you must try to convince the opposing character to give you something. Successful persuasion is reliant on you reading the other character's emotional state and his/her reactions to what you say. More importantly, these are one-shot deals. Mess up a major conversation and piss off a character, and that's it. You've just blown your shot. There are no do-overs.

Adding to the immersion of the game is the haunting musical score that plays throughout. The quality of music cannot be understated, as the environmental soundtrack adds much to the totality of the experience. Shifting between ambient and upbeat when needed, the music in Deus Ex: Human Revolution is a perfect fit for the tone of the game. Sound effects are also top-notch, with positional audio being key if you're attempting to play it as a stealth game. If you're not playing Deus Ex: Human Revolution with a full surround setup, you're missing out.

To be fair, we did encounter a few minor technical hiccups while playing, such as a slight delay whenever an Achievement fired off, some visual pop-in and the occasional clipping error, but none of the aforementioned bugs were enough to knock us out of the world that Eidos Montreal had created for us to explore.

Some will probably compare the Deus Ex: Human Revolution experience to that of a film, but playing through the game is more like reading a good book. The game layers on so many different elements, the more you discover, the more you want to keep pushing forward to see what's next. And just like a good book, Deus Ex: Human Revolution is incredibly hard to put down.

No matter what genre of play you prefer, Deus Ex: Human Revolution is bound to fit the bill. It is a brilliantly constructed game that sets up a world and then sets the player loose, allowing you to explore as you see fit. From the art direction to the genre-bending gameplay, Deus Ex: Human Revolution is a landmark in game design that is sure to be referenced in the years to come. Buy it without hesitation.

Score: 9.7/10