By Neil McGreevy BBC

The game is brimming with vivid colours and sounds

Many will be those quick to hail Sony's latest effort, LocoRoco, as a work of original genius.

But lurking underneath LocoRoco's pretty fa�ade is a cocktail of Yoshi, Katamari, Vib Ribbon, Kirby and Marble Madness. It is also the best PlayStation Portable (PSP) game to date.

Globally, it is no secret that DS sales have been edging out the PSP. Nintendo's sublime understanding of what makes a good portable game has trumped Sony so far in the software stakes.

In a market where most decent PSP titles are scaled-down versions of console franchises, LocoRoco is that rare beast.

It is a game designed completely from the ground up for the machine; a proper handheld experience that is perfect for short joyous blasts.

Blobbing around

Gameplay is simple. Guide your fat gelatinous blob to the end of each meandering level, finding secrets, battling the odd enemy and picking up compadres en route.

LOCOROCO Format: PSP Graphics: 8 Sound: 9 Gameplay: 9 Enduring appeal: 8 Overall: 8.5

Rather than controlling your LocoRoco, players press a button to tilt the screen and coax the blob to the goal. It can also split into a gaggle of tiny blobs to traverse tight spots.

The game offers a rich, multilayered trifle of platforming and puzzles. Each cheery screen is a work of design genius that would not look out of place in a Lemon Jelly video.

It populated by such bizarre characterisations and pitch-perfect obstacles that you half suspect that Nintendo's Miyamoto has been moonlighting at Sony Towers.

Music also plays a huge part in the game's success. Each level rings out to a rich score peppered with your blob's babblings.

Pick up enough of the musical oddities and they will play choir to the music, building in harmony as their numbers swell and changing in tone depending on the type of LocoRoco you are using.

Travelling companion

A work of undiluted Japanese whimsy, this deserves to be a massive success.

LocoRoco is a platform game with a twist of cuteness

But it will no doubt join the cultish ranks of Vib Ribbon, Katamari and Ico.

Everything gels perfectly and, due to its simplicity, that PSP bugbear of heavy loading times is not even an issue, making this the ideal travelling companion.

It is not all perfect. The controls can feel sluggish at times, while the overall pace is just a little too sedate for its own good.

Minor quibbles aside, LocoRoco is a PSP essential and the perfect antidote to the current overkill of driving and shooting fests.

This is the best game Nintendo never made.