What lets the game down the most are the controls. From a design perspective you can applaud the developers in their endeavours to use the dual screen features of the Nintendo DS - and in many respects they have been quite innovative in their approach. The upper screen is reserved for the 3D action while the bottom touch screen is used for camera commands, weapon selection and the viewing system (infrared night vision etc).

All of these features are individually well presented; however when combined into one control system the term "chaos theory" comes into play - literally. In a game where all the action is happening in the top screen, fine controls being usurped by thumb control on the touch screen make for an awkward and at times frustrating experience.

Sam Fisher has been delivered to the Nintendo DS with a lot of movement options. These include the ability to crouch, ladder climb, shimmy on ledges, slide down pipes and split jump on walls. These are all great options that add a lot of depth to the game, but the limitations of the control system - and in particular the awkward camera controls - often make these moves difficult to pull off. The graphics in Tom Clancy's Splinter Cell: Chaos Theory are good, but the sudden changes in camera position as you pass into different areas or structures are not a smooth transition and tend to distract as you pull out your thumbs to readjust the camera to a better position. The whole effect can be quite confusing.

Splinter Cell relies on players making the best use of shadow for concealment, and in this regard some of the graphic limitations of the handheld become evident. The changes in light are subtle and not obvious in places, and coupled with the sudden camera changes, it can be difficult to maintain concealment. There are also some horrible graphics glitches where you can stick Same Fisher's head and body in and through walls. These are obvious bugs and should have been sorted out early in the development process. You are left wondering if perhaps this was a rushed release.

The game comes with sub-games. These consist of quite a neat little lock picking challenge and a code key panel challenge. Missions are challenging in themselves, and often are delivered through a comprehensive text description; too long in most missions, when you are just wanting to get into the action.

The multi-player setup allows from two to four players to play in both a co-operative mode or in a head-to-head competition. Head-to-head consists of mercenaries versus the spies. Game parameters include spies running to hack into devices while the mercenaries defend them.

Overall, Tom Clancy's Splinter Cell: Chaos Theory has buckets of potential, but it is let down by poor controls, camera switching issues and low light levels. These drawbacks ultimately make it a game that will only appeal to hardened fans of the series. These in turn may well lament what may have been.