It says a lot about the absurdity of the Circle Pad Pro that when its existence was leaked last year, some hardcore Nintendo supporters refused to believe it was real. The concept of adding an additional analogue stick to the machine by the way of a chunky add-on seemed almost unbelievable; surely Nintendo wouldn’t deliberately handicap the console's portability in such a crude fashion?

Alas, such hopes were in vain. Whether it was rumoured pressure from Capcom or Nintendo`s sudden realisation that it had missed that all-important second analogue slider off the 3DS blueprint, the Circle Pad Pro is very much a reality- - and even the most die-hard Nintendo fan will admit that it’s a rather ugly one at that.

Attempting to augment a portable console’s capabilities with physical add-ons is always going to be a largely thankless task, and Nintendo has done the best possible job with the Circle Pad Pro. Granted, it's an eyesore when attached to the machine itself, destroying any semblance of symmetry that might have been there previously. The combined set up looks lop-sided and bulbous, and creates a hybrid device which doesn’t exactly scream mobility.

Still, it’s not a complete disaster. In fact, many 3DS owners may find that the Circle Pad Pro offers a more comfortable gaming solution. Since launch, many players have complained of hand cramp after prolonged gaming; the newly increased bulk and ergonomic design solves that particular problem, even if it makes the console look like it's fallen from the ugly tree and hit every branch on the way down.

As well as the obvious second slider, the Circle Pad Pro has three new buttons. The ZL and ZR triggers are pretty self-explanatory, but the inclusion of a second R trigger is initially confusing. That is, until you realise that the R trigger on the 3DS console is almost impossible to reach when the Circle Pad Pro is fitted.

Because the Circle Pad Pro uses an infra-red connection to link with the 3DS, it requires one AAA battery. It’s almost inconceivable that such a peripheral should demand its own power supply, but with almost 500 hours of usage offered on a single battery, it`s not like you`re going to spend all your spare cash on fresh packs. Bizarrely, the battery itself is located in a compartment which is locked in place by a metal disc. You’ll need a tool — like a screwdriver, penknife or trusty coin — to open this. It might seem like overkill, but we imagine it’s been done to ensure that younger players don’t tinker with the unit.

Of course, with this kind of product, the proof really is in the pudding. As soon as you play a game which uses the additional control options, you’ll find yourself slowly warming to this unusual peripheral. Resident Evil Revelations — which plays perfectly well without the extra slider pad (so good in fact that we awarded it 9/10 in our Resident Evil Revelations review recently) — is improved dramatically when the Circle Pad Pro is called into play. Although the Resident Evil series isn’t built around FPS-style dual-stick controls, the configuration offered by this accessory feels incredibly intuitive.

Of course, Capcom’s survival horror epic is merely the tip of the iceberg. Kid Icarus: Uprising and Metal Gear Solid: Snake Eater 3D both promise support for the add-on; we honestly can’t imagine playing the latter without twin-stick controls, so it may well prove to be an essential purchase.

Nevertheless, the Circle Pad Pro is a largely needless exercise. Nintendo really should have taken note of market trends and included an additional analogue pad when the 3DS launched a year ago. The decision not to is made all the more galling by the fact that PSP owners have been lamenting the lack of a second pad on their console for years — it’s not as if Nintendo didn’t have any prior warning before that started developing the 3DS.

We’re pretty sure that a 3DS hardware revision is in the offing, and will join the GBA SP and DS Lite in Nintendo’s ever-expanding library of console face-lifts. Expect the next 3DS to come with that second slider, but in the meantime, the Circle Pad Pro is your only hope. While it’s true that most games will be perfectly playable without it, the improved controls and increased comfort make it an appealing prospect — even if it’s less than attractive from a visual perspective.