The premise in Amplitude is actually fairly simple although first-timers may find the game slightly confusing at first. Therefore we definitely recommend you run through the well put-together training sessions before launching into the game proper (we also recommend you start the game on an easy setting!). Essentially gameplay involves pressing one of three assigned buttons at the right time to fire lasers at small capsules to release "musical energy". Training will also show you how to use the several power-ups in the game.

It all works like this then. Each "level" contains several songs and in order to progress you must "beat" or "unlock" each song. To do this you pilot a type of spacecraft vehicle armed with 3 lasers. Each laser is operated by a button on the controlller which you can customise to suit your preference or comfort. At the start of each song your craft appears out of a swirling mist and flies into a third-person position over a series of 8 multi-coloured tracks. Each track represents a part of the song - drum tracks, bass, synth, guitar or vocals - and is divided into sections or bars and dotted with capsules containing the earlier-mentioned musical energy.

On each track the capsules can sit to the left, centre or right and these 3 positions correspond to the 3 lasers on your craft. The aim is to match the laser to the capsule position and blast every single one in each section thus releasing all the musical energy. This then "energises" that section so that it plays automatically for a short period of time. While it's playing by itself you can then flick over to another track by using the d-pad or left analogue stick and repeat the process to unlock another part of the song. If you manage to keep up you can have all parts of the song playing and it's then a matter of flicking back and forth to re-energise each track as they stop. Believe us when we say it all sounds quite simple here but it gets pretty challenging quickly!

Certain sections of track also contain special capsules and when you blast all of them you'll unlock one of several power-ups which can then be used by pressing X. The best of these will blast a whole section of track in one hit thus unlocking it while another will slow everything right down making it easier to blast trickier sections. As you rock on down your tracks blasting as many capsules as possible the beat itself is mirrored perfectly by the vibrations in your dualshock too which is quite a nifty little feature and helpful as well!

One of the main differences those who played Frequency will notice is not only the increased number of tracks (8 now instead of a maximum of 6) but also the track layout. Frequency featured tracks placed on a cylinder that could quickly be rotated back and forth. Amplitude's 8 tracks though are now laid side-by-side on a slight arc which in itself increases gameplay difficulty by the fact that you can now only shift left and right from one side to the other. You'll see what we mean when you start playing some of the faster, more difficult tracks as quick fingers indeed are required.

Apart from that though the numerous tweaks to "general" gameplay are fairly subtle but they all work towards creating a near-perfect single-player game that builds on Frequency's already solid base. The biggest changes then are to be found in Amplitudes other game modes.

Remix mode for instance has undergone a bit of a rebuild. For the uninitiated this is where you can get creative and make new remixes of all the songs in the game. You can choose to make a remix from scratch using blank tracks or remix an existing version. Each mix is broken into different parts of the song - intro, verse 1, verse 2, chorus, break, etc - and you can remix each of these sections before moving onto the next. Once completed you can then play back the whole remix and if you're happy with the finished product it can be saved to memory card. There are several settings and effects that can be adjusted via the right analogue stick including loop, speed (bpm), chorus, stutter and delay.

The only niggling thing here is that the vocals and part of the melody are enabled the whole time and can't be edited which is a bit of a pity. However the big bonus is being able to use saved remixes to play back in single-player AND in multiplayer both off- and online!

And it's the multiplayer modes where the other great improvements have been made! Amplitude includes 2- and 4-player modes on a single screen plus several online games. Unfortunately in NZ we were unable to test the online modes at time of review due to a lack of network support in this country but according to overseas sources Amplitude includes a nice peer-to-peer feature for those lucky enough to own an imported Network Adaptor. This essentially means you can connect directly to another player rather than messing around going through specially set-up servers.

There's a host of multiplayer games with one of the most interesting being Duel, a musical version of HORSE which is popular in games like Tony Hawk's Pro Skater. Here you and an opponent try to play a track better than each other until one player earns all the letters to spell Amplitude.

Graphically Amplitude again shows improvements allround over it's predecessor making it a more polished product overall. There's no revolutionary mind-blowing stuff here as the visuals are merely a backdrop for the musical gameplay but there's more stuff happening than in the original game, it's prettier and it's very colourful! As in Frequency you also get to create your own "Freq", your customised onscreen character who appears in a little window during gameplay and plays instruments from whatever track you happen to be on at the time. It's a nice touch and adds to all the flashing signs, music video snippets and swirling colours to create a truly unique visual experience. Load times are quick and the framerate is generally quite solid apart from the odd hardly noticeable little chug here and there during the most intense sections.

Sound. THE most important component of a music game! It's all good here people we're pleased to say being cleanly and crisply presented in Dolby Pro Logic II. Developers Harmonix have included a much more varied collection of tracks and more of them than in Frequency and the selection on offer should appeal to a much broader cross-section of gamers. There are old-schoolers like Herbie Hancock, David Bowie and Run DMC mixed up here with the likes of Blink 182, P.O.D., Pink and even a little bit of the heavy stuff with the inclusion of I Am Hated by Slipknot. There's also some pure dance tracks in various styles so there's plenty here to keep everyone happy.

Also we saved mentioning another game mode till now - Soundtrack. Here you get to listen to all the tracks you unlock in the game either in the order they appear in the list, randomly or by creating your own custom playlist. This might be just what you were looking for for that next party!