There's probably an unwritten rule somewhere: If you're a keen gamer, at some point you're undoubtedly going to own a copy of (or at least play) Mario Kart. The First Law of Nintendo, if you will. It's not really surprising, given that Nintendo have produced a version of Mario Kart for practically all of their consoles since time immemorial, which means that this particular version has a massive reputation to live up to. With wireless internet play and dual-screen support, hopes were high for Mario Kart's DS incarnation. Have they been realised? Pleasingly, on the whole, they have.

Despite the core game being as old as the proverbial hills, Mario Kart DS still feels fresh to play and, most importantly, is still fun. In fact, fun is an understatement. It's arguably the most outright enjoyable title on the DS. The combination of track design, visual panache, maddeningly addictive music and perfectly-honed gameplay (and after umpteen iterations of essentially the same game, it should be perfectly-honed by now) makes it very hard to put down. This is due in no small part to the new tracks and features added to take advantage of the DS's capabilities.

The game hasn't been radically tweaked, on the contrary, but the subtle changes they have made really enhance the game. The most obvious of these is the support of the second screen. The top screen of the DS is the main view in which you do all the racing, whilst the bottom screen provides you with information about lap times, race positions, what items any particular player may currently have, and most importantly, a map of the course. Using the Y button or touching the screen will switch the view between a map of the entire track or a zoomed in view of the section you are racing. The whole circuit map is only really of use to help you learn the circuits, or perhaps to help you gauge when you should launch that last ditch assault with the red 'Simpson' shells (they're homers, see?) you've been saving for the last lap and a half. The partial course view, whilst more limited in scope, does have its advantages.

Firstly, it allows you to judge where and when to drop items, as it allows you to track the players behind you and drop items directly into their path. It can also help you time the dropping or dangling of items to prevent your kart being turned over by a shell (barring the Spiny blue shell, from which there is no defence). It also can help you avoid losing too much time if you're sprayed by the ink of a Blooper, as even though your view in the top screen is obscured, you can still navigate the corners by timing your drifts using the map view. It's not just useful in Grand Prix or Vs mode: In Time Trial mode, the zoomed in view will show markers on the track, letting you keep tabs on the racing line you've been steering, which helps you learn from your Ghost data whether you're taking a corner in the fastest possible way. It can also be used to help you find objectives in the Mission mode and aid your situational awareness in Battle mode. Canny players will learn to divide their attention between the top and bottom screens to maximise the effectiveness of the items they pick up and even time when to intentionally drop out of the lead of a race when one of the tail-enders unleashes a Spiny Shell to avoid being caught in the blast. It adds an extra, thinking dimension to an already fast and frantic experience.

Graphically, the game is good: easily on a par with its console-based predecessors, and the frame rate is beautifully fast and smooth (offline, at least). You may suffer a few lag problems during online play, particularly if the group you're racing with is particularly cosmopolitan, but nothing that will spoil your enjoyment too much. Nintendo have really gone to town with some of the new tracks, though a couple (such as the Figure-8 circuit) may disappoint series veterans with their simplicity. My favourite amongst the new tracks has to be Rainbow Road: a space-born psychedelic Mobius strip. As challenging as it is pretty, the track contains both a loop and a corkscrew, which are particularly disorienting the first couple of times you drive them. The selection of tracks from previous versions of Mario Kart (to form the Retro Grand Prix) is good, on the whole, though there are a couple of bizarre inclusions, such as Baby Park and Luigi Circuit.

An entirely new mode of play created for the DS is the Mission mode: six stages comprising of eight missions (plus one Boss battle) each. They take place on bite-sized sections of the Grand Prix tracks, where you have to fulfil certain objectives, such as driving through a set of gates in order, or collecting coins, within a time limit. They start getting tricky around the third stage of missions, and are real tests of how well you can handle the karts.

Whilst there's plenty of mileage in the offline single-player mode, it's multiplayer or online play where you're likely to get the most enjoyment. As good as the AI of the CPU players is, nothing beats the experience of racing other people. It's here that I should sound a note of caution, however. From my own experiences and through talking to other owners of the game, getting Mario Kart to work with your wireless network is an exercise in pot luck. I know people who've had absolutely no problems at all, others complain of their network being unable to give their DS an IP address, and for me, the game point blank refused to detect my wireless network, even when sat two feet from the router, with no amount of tweaking with settings on the router or with the manual setup within the game itself doing any good at all. Thankfully for me, most of my local pubs are supporting the free WiFi scheme Nintendo have set up with BTOpenworld and TheCloud, which means I don't have to fork out an extra thirty-odd quid on one of Nintendo's USB WiFi dongles. Not that I needed much of an excuse to go to the pub, anyway... You'd be well advised to check whether the game supports your wireless router before buying the game. Hopefully this issue will be something Nintendo can fix for future wireless-enabled games.

Once you have a wireless connection set up, joining an internet game is a breeze, but sadly you can only play in VS races, with Battle mode limited to local wireless play only. Battle mode contains two game types, Balloon Battle and Shine Runners, the former of which is notable for being able to use the microphone to inflate your reserve balloons once they've been burst (by blowing into the mic). There are half a dozen Battle maps, including a wonderfully modelled Nintendo DS and a fruit tart that splashes your top screen if you run into one of the dollops of whipped cream. The most fun, though, is arguably found in the VS mode (even though this is limited to four players online and some of the more complex tracks aren't playable), and it's here where I should really explain why the game is so fun to play.

It's not just the wonderful aesthetic feel to the game, nor the pureness of the handling of the karts, it's that sensation that everything is just right. It's hard to explain, but it manifests itself the most when you play other people. Despite the sweet cartoon looks and catchy teeny-bopper soundtrack, Mario Kart is one of the most evil games created by man. It's the sheer callous, calculated cruelty of it all. When you play online you know as well as everyone else that being first over the line starting the final lap is a sure-fire recipe for finishing last. You'll see players jockeying for places whilst being careful to avoid being a target, saving power-ups until the last possible moment, and then smiting the devastating blow with a seeker shell two corners from the finish on the final lap that enables them to steal victory. There's a fine line between being the fall guy and being the victor, the fun of the game being all the treacherous backstabbing, hitting other players when they're utterly defenceless, whilst walking it. Mario Kart is concentrated joy, frustration, elation and disappointment, all packed into a tiny game card. Is it the best Mario Kart ever? Maybe, but whether you think it is or not, you'll want to play it until your fingers develop arthritis.