Genre: Shooter
Publisher: Q Entertainment
Developer: Q Entertainment/Hexadrive
Release Date: Q1 2008

Don't feel bad if you haven't heard of Rez; it's one of those incredibly obscure video games that makes cult hits Psychonauts and Beyond Good and Evil look positively popular. The brainchild of Tetsuya Mizuguchi, Rez is an unusual mix of music game and rail shooter that, quite frankly, was just too bizarre and unusual for all but the most hardcore gamers to take more than a half-hearted glance at, despite wide critical acclaim.

Released for the Playstation 2 and Dreamcast (although the Dreamcast version only came out in Europe and Japan), Rez vanished into video game history not long after it came out. Despite being reprinted toward the end of the PlayStation 2's life cycle, Rez is still one of the hardest-to-find titles for the system, and many gamers have never gotten the chance to try out this rare gem. Luckily, Q Entertainment, Tetsuya Mizuguchi's current company, and Microsoft have banded together to bring it to a whole new audience with the Xbox Live Arcade port, Rez HD.

Rez HD thrusts you into a not-too-distant future world where human overpopulation has begun to take its toll on all elements of society. There were so many humans in the world and so much information created by them that the current computer programs couldn't keep up. Society was beginning to collapse in a wave of riots and crime, until a new system, Project-K, was created. Project-K was built around a new AI program, Eden, who was created to manage the flow of information. However, the nonstop flow of human information into Eden caused the AI to become sentient; unable to deal with the confusing and confliction information caused by humanity, Eden decided to shut itself down. You play as an unnamed hacker who must enter Eden's system, fight way past its defenses and reboot Eden before society once again begins to collapse without its guidance.

However, the nonstop flow of human information into Eden caused the artificial intelligence sentient.

Rez HD's description is fairly simple, but really doesn't do it justice. It's a rail shooter, in every sense of the word. Players take control of the unnamed hacker as he flies through the various defensive levels, blasting through the corrupt Eden system's defenses and hacking through the various layers of defenses. The controls are incredibly easy to learn: The analog stick moves the player's crosshairs around, holding the A button allows the player to lock onto enemies, and releasing it fires. It's simple to pick up and yet maddeningly addictive to master. The hacker can lock onto a maximum of eight enemies at once, and the more you lock onto, the greater a score multiplier you receive. While it's entirely possible to burn through stages in Rez just by blasting everything you see without rhyme or reason, true masters will have to learn how to lock on to as many enemies as possible without getting bombarded by attacks or losing sight of their foes.

Beyond the aim-and-shoot gameplay, Rez has a few other twists and turns that give the gameplay extra depth. Each of Rez's five levels is divided into 10 different "layers." To advance through a layer, the player must hack a specific target by shooting it eight times; in order to fully complete the stage, the player must hack all 10 layers before the boss appears. While completing all five layers on their own is fairly easy, the real challenge is balancing the hacking with defeating foes. Hack too early, and you miss out on precious points that could easily be the difference between a high score and failure. Hack too late, and you won't reach the higher layers, which means you'll miss out on even more points. It's a careful balance that must be maintained. Likewise, long and successful combos can also give the player access to life-ups, which change the hacker's avatar from a formless blob to a perfect humanoid form, and Overloads, which blast everything on the screen for massive damage and tons of points.

At the end of each stage, players will face a deadly shape-shifting boss. These creatures don't have any rhyme or reason, twisting and changing into a number of different and unique forms. One may turn into a deadly cylinder of crushing blocks, and then into a series of laser-tipped vines that attempt to launch deadly blasts at the hacker, before switching into a UFO that fires volleys of missiles — and that's just one boss! Defeating these bosses involves surviving the attack patterns until their "core" becomes vulnerable and you can damage them; it's quite simple in concept, but with the bosses' unusual designs, it remains thrilling to the very last second.

Now, all of the above sounds like a fairly average rail shooter, and in many ways, Rez is indeed just that. Where Rez really excels is in its visual and audio presentation; it's a rare game that can also be described as artwork, although it's almost impossible to describe in any way that does it justice. Perhaps the only real way to truly explain Rez is to call it Synesthesia in video game form.

As players guide their hacker through the wireframe Tron-esque computer world, the entire level pulses and pounds along to the techno beat. Fire your weapons and you alter the beat, but never in an unnatural way; your laser even fires to the rhythm of the music. Destroy enemies, and they'll add a pounding bass rhythm to the level, while at the same time creating a dazzling light show. Your controller even vibrates to the rhythm of the actions. While all of this may sound mundane on paper, when you're actually playing, it becomes an almost incomparable video game experience. It's hypnotic and soothing while simultaneously being intense and dramatic, and you're not just blowing up enemies and defeating bosses — you're creating your own music and light shows. It's one of the few games that must be experienced in order to understand. Even better, Rez HD's new high-definition mode makes it look even better than it has before, although returning fans can always play the original Rez mode, if they wish.

Rez, despite being fairly short, has a hefty amount of replay value; a number of new Beyond modes unlock once you beat the game, offering modified levels, score attacks and various other secrets. These definitely extend the game's value long beyond what you'd get from simply running through the original five stages. While it's entirely possible for unskilled players to run through the regular modes without too much frustration, true Rez masters are going to want to run through these various modes a few times to attain the highest possible scores. These scores can then be uploaded to Xbox Live for other gamers to compete against, ensuring that, much like its spiritual brother Geometry Wars, Rez's length is no indication of its replay value.

Rez HD is a picture-perfect remake of a classic niche title. It retains all of the addictive trace-like gameplay that made the original Rez so much fun and combines it with updated visuals that take advantage of the technology that's now available to gamers. When combined with the massive amount of unlockable extras, the competitive online scoreboards and addictive gameplay, Rez HD is shaping up to be one of the best deals in the Xbox Live Arcade. Whether you're a returning fan or a curious newcomer, Rez HD is sure to delight, and at only 800 Microsoft points, it's also a real bargain compared to the hard-to-find PS2 and Dreamcast versions.