Fresh takes on old franchises are back in style. But rebooting a beloved classic franchise that died a decade ago without missing a beat is a tall order.

That’s the uphill battle Square Enix faces with Deus Ex: Human Revolution, except the company isn’t just trying to reboot a typical cult classic; it’s trying to recapture the magic of a franchise that was already critically acclaimed.

The original Deus Ex title has a standing score of 90 out of 100 across 28 reviews on review aggregation site Metacritic. The sequel, Deus Ex: Invisible War, wasn’t as good as the original but still has a score of 80 out of 100 across 44 reviews and a whole batch of perfect scores. And there are even running jokes on the Internet that whenever someone mentions Deus Ex, everyone has to go re-install the game and play through it again. (I’m doing the same right now myself.)

Square Enix might be up to the task if you go by the demo it showed off at the Electronic Entertainment Expo today in Los Angeles, Calif. I got a chance to play through the introductory level that featured the series’ protagonist, Adam Jensen, trying to retake a biotech corporation under siege by human “purists.”

The purists in the game are people who think that human augmentation, a key trope in the Deus Ex universe, is a crime against nature. Human augmentation is basically adding cybernetic enhancements like bionic arms and eyes that improve strength and eyesight. It’s typically used to help paraplegics and other handicapped individuals, but it can be used for mercenaries to make them better soldiers. Jensen is one of those mercenaries, having lost his limbs in an attack. It gives him some unique abilities with his cybernetic enhancements, but at its core the game is still a first-person shooter (FPS).

Running and gunning is difficult in this game. At least with the character build Square Enix showed off at the show. Inexperienced FPS players will probably be flattened by a hail of gunfire the second they stand up. It’s possible to take advantage of the game’s cover-based shooting mechanics, but they are a bit clunky compared to other cover-based shooters like Gears of War. Once you get the hang of it, though, it’s good enough. Most enemies go down in one or two shots, and they’re nice enough to stay in one place under cover for a while before they try to flank you.

Jensen has a few tricks up his sleeve, though, that make taking a stealthy approach better than charging in with guns blazing. He can throw gas and concussion grenades to incapacitate enemies and can deliver a quick non-lethal melee attack to remove an enemy from combat after sneaking up behind them. He can also activate a stealth field, but it only works for 7 seconds. The melee system is frustrating, though, because it takes time to recharge Jensen’s take-down ability and the game executes a cinematic whenever you try to incapacitate an enemy that leaves you standing up and makes it easy for you to get caught. It uses the same energy bar that your other skills, like the stealth cloak, use.

First impressions suggest the FPS elements are what you would expect with other games. Players can combine certain elements of their inventory to enhance their weapons. That can include adding augmented pieces of equipment like a silencer or a laser sight to turning a pistol into a straight up grenade launcher with explosive rounds. I started the level with a tranquilizer sniper rifle, but found it was pretty useless as soon as I got a pistol with a silencer and gave up on the non-lethal approach because it was so hard to move through the level stealthily.

The game also has role-playing elements in it with Praxis Points, which give Jensen access to new augmentations. That can improve Jensen’s armor, his jumping and his speed or give him access to new skills like the stealth cloak or the ability to see through walls. Those powers drain his energy — the same pool of energy that has to be full to execute a melee attack — and it takes upwards of 15 to 20 seconds to recharge fully. Jensen can have up to 5 bars of energy, but only the first bar recharges automatically. The rest have to be recharged with items, which makes the use of skills even more limited.

Even while being stealthy, though, the game is frustratingly difficult. The enemies spot you very quickly and the cover system is pretty glitchy and sometimes reveals you when you think you are still hidden. The cinematics leave you trapped in the open for several seconds, letting enemies easily catch you when you really mean to just run in and drop an enemy and quickly jump out, so that kind of kills the whole non-lethal stealth approach. Then there’s the tranquilizing system, but the darts sometimes don’t put an enemy to sleep right away and they alert other enemies to your presence.

You can die very quickly. I understand the game is trying to be realistic, but you can be taken down by three or four shots. As soon as two enemies converge, you’re probably going to die unless you have a machine pistol or some kind of powerful gun. Ammo in the game is pretty scarce, and even though it takes only a few shots to take down an enemy, it’s easy to quickly run out of ammo and be left helpless with just a melee attack — which will again expose you and get you killed.

There are plenty of examples of failures to reboot a classic series. One example is NiGHTS: Journey of Dreams — a reboot of the cult classic NiGHTS into Dreams title from the Sega Saturn. The game earned a score of 69 out of 100 across 47 reviews and was a pretty mediocre experience. It was the last game I bought without checking a review score, because I had high hopes that it would capture the same magic the free-floating jesters on the Sega Saturn title had.

After playing the original Deus Ex for more hours than I can count, I don’t know if I’d pick up Deus Ex: Human Revolution on a knee-jerk reaction out of my love for the original game. There are lots of good things about the game, and the difficulty might taper off as players get access to better armor and guns. But the energy system is difficult to handle and not having an efficient melee takedown system really hurts the stealth aspect of the game, turning it into a pretty straightforward cover shooter.

Deus Ex: Human Revolution comes out August 23 and will be available on Xbox 360, PlayStation 3, Windows computers and OnLive.

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