One of the most criminally over-looked games of this century to date has just been released to a whole new audience on Xbox Live Arcade.

Rez HD is an enhanced Hi-Def Widescreen version of the classic Rez, released in 2001 for Dreamcast and Playstation 2. Created by Tetsuya Mizuguchi (now best known for Lumines and Meteos), Rez was his first, and in my opinion finest, experiment of integrating music as a gameplay mechanic instead of leaving it as just background noise.

The object of the game is simple. You play as a hacker, forcing your way through the Project-K World Computer Network, trying to eliminate viruses and firewalls that have shut down the network's resident A.I. "Eden". Your job is to restore Eden, and prevent the collapse of computer dependant society.

Game play, at it's most basic form, is an on-rails style shoot 'em up. You guide your avatar through five areas, each comprised of 10 layers. You progress through layers by locking on up to eight viruses at a time with your laser, and destroying each Network Opening you find. Enemies will sometimes leave power ups that can evolve your avatar through seven different forms - each becoming more human in shape than the previous. However, take one hit from an enemy and your avatar will devolve.

The game at this point may sound like just a regular boring shooter, but this couldn't be further from the truth... although explaining the reasons why are very difficult indeed. Rez HD is a fantastic experiment with Synaesthesia, which is merging and overlapping senses, similar to the Russian painter Kandinsky's work. It's not just the game play that gets you hooked, but the euphoric blend of astounding visuals, pleasing sound, and addictive play. The levels actually react to the beats of the music, changing the rhythm of your laser, and actually morphing the terrain you fly over. The music and sounds also change completely whenever you evolve your avatar's form.

Rez HD is a fantastic upgrade to the original (which is included in the game). Not only do the HD visuals look even more stunning than ever before, but the music now has been up-sampled to true 5.1 audio, and you can change the graphics and sound with filters (I recommend checking out Bloom and Glare modes with the Underwater sound environment). There's also a ton of replayability thanks to score attack and Beyond modes, along with an absolute deluge of unlockable extras.

For 800 Microsoft Points, Rez HD is an absolute steal, and you owe it to yourselves to experience this wonderful game. I'd give it 6 out of 5 if I could.

Rez HD is available now, priced at 800 Microsoft Points.

Rez HD is rated 3+ by the PEGI.

Rez HD is rated E (Everyone) by the ESRB for Mild Violence.