Invizimals

If you're wandering around fruitlessly, the game even tells you what to look for. The answer is generally colour, and you can speed through the early capture missions simply by investing in a pack of coloured paper. Things get trickier as you work your way through the 123 Invizimals in the game, and the illusion that you're unearthing these creatures from your home environment doesn't last long when faced with the game's sometimes quirky implementation.

As an example, here's what happened when I had to find and capture a Moonhowler Pup. The game prompted me to find something purple. I'm not Prince, so this wasn't as easy as it sounds. Part of the game's appeal is, of course, that it will send you scampering around the house, seeking out the triggers you need, but when the game is so fussy, it can't help feel limiting - especially since the single-player mode essentially hits a dead end until you unlock the Invizimal in question.

I ransacked my three-year-old daughter's wardrobe for a variety of purple-pink t-shirts, but none of these could raise the proximity detector all the way. In the end, I cracked the problem using a soft toy of a Ribena Berry. This, it transpired, was the perfect hue - but it wasn't a flat surface. I ended up holding the cuddly fruit up to the light, so the camera would lock the target, then simply pointed the camera at the capture card, lying on a plain wooden table. It worked, but in doing so bent the rules so much that the idea of tracking down hidden creatures was rendered completely abstract.

The mini-game to capture this diminutive vulpine critter also required me to sneak up on it and shout. CGI grass sprouts up around the image of the capture card, and you have to bring your PSP in low and get behind the Invizimal before bellowing to scare it into submission. Quite apart from the indignity of screaming at a tiny wolf-thing that wasn't really there - this being the latest in a long series of gaming moments that have made my wife look at me with pity and sadness - the camera struggles to cope when the capture card isn't perfectly framed.

Much like EyePet, it relies on the black and white card design to tell it how to orientate the graphics in the real world, but go too low and it can no longer register the image. With the creature flicking in and out of existence, and the small microphone struggling to acknowledge that I'm shouting in the correct way, a simple task is suddenly really irritating, and I'm fighting technology rather than the game.

This is a problem throughout single-player, as it tries to keep the gameplay varied while necessity forces you to do the same thing over and over. Some mini-games are engaging - catching Sting Wing by swatting her with your hand is a great example of how the fun and immersive the technology is when it works - but others stretch the small, fragile camera and its software beyond its comfort zone. Using the camera as a surrogate motion sensor to steer Bearserker through a timed slalom is just annoying, while guiding Skysaur through a barrage of fireballs seems to rely as much on luck as your movements.

Still, if the single-player side of things feels stodgy and prescriptive, this is balanced out somewhat by an admirable brace of multiplayer options. Available across both ad hoc and infrastructure connections, there's freedom here that the corridor-style story can't offer. You can challenge another player to a one-off duel, or set up your own Invizimals club for more long-term combat options with like-minded friends.

There's also a smart approach to trading, with a freeform barter system that allows players to dictate what they feel is a fair swap. In other words, you can put up whatever combination of creatures, vectors and sparks you feel is required to secure a desirable trade, and your partner can tweak the offering accordingly. While solo play quickly grows repetitive, it's here that the game's longevity lies for those who put in the hours.