There's a strange advertising poster currently stalking the bus stop hoardings. It depicts a group of twentysomethings sitting around a table having fun, and along the top of it there's a crude staccato strapline: "having a laugh/in the pub on a Sunday/sitting with mates/drinking Gaymers over ice."

We suspect the copywriter went on a bender the night before the client meeting and resorted to submitting his notes. However, the idea of describing a product in this stream-of-consciousness way is interesting, and it may help you to grasp the essence of SolaRola if this reviewer submits an extract from his own notes.

Here we go: "Destroy a patch of green, explosion tilts the screen and sends rocks cascading through the crater hole – makes you happy." This essentially sums SolaRola up.

An unabashed tribute to celebrated PSP platformer LocoRoco, SolaRola just damn well makes you happy, not because the characters are especially amusing (although they have their moments) or the jokes particularly sharp (ditto), but because simply being in the game's bizarre, malleable, well-meaning universe is a joy.

You play as Waz, one of two circular brothers travelling around together in a spaceship. Each level involves beaming down onto a themed planet – including one called Omicron P8 (kudos to the first person to tell us where this comes from) – to save the universe, but there are occasional deviations from the more 'serious' narrative to carry out chores like taking out the rubbish and retrieving travel sickness medication from your home planet to keep Wiz from vomiting.

SolaRola's simple, surreal, wrapping-paper environments are beautiful, and the animation flows and swivels with the incongruous fluidity of a cartoon. And since this fluidity is also central to Waz's movement, it's impossible to divorce graphics from gameplay: SolaRola's look is also its feel.

Waz moves by rolling, bouncing and distending like a water balloon over the hillocky terrain, oozing down narrow channels and jostling between moveable objects. Pushing left or right causes the whole level to tilt, pinioning around Waz's centre, so that moving faster really means increasing the gradient of the slope you're rolling down.

The entire game consists of very few elements. There are cherry bombs that destroy clumps of green material and kill the various baddies; there are wagons made of two circles tied together; there are boulders that you pull with your mouth; there are clouds that gradually dissolve on contact; there are surfaces that act as trampolines; and there are swings. From these few threads, however, SolaRola spins an astonishingly rich tapestry of ideas.

One minute, you're timing a series of jumps, while the next you're using a trampoline to propel bombs into the path of flying creatures. Then, you're using the boulder you've just starting dragging to suspend your weight as you abseil under a platform. Or, you're falling slowly through a cluster of shrinking circles, trying to clear a path for a boulder that you need to follow you down.

The variety of activities in SolaRola is remarkable, but equally remarkable is the fact that all of them happen organically in the universe developer Progressive Media has created. The game's constituent parts are so perfectly designed that they can combine in a multitude of unforced permutations. SolaRola has the versatility of Lego and the tactile appeal of silly putty.

In fact, the simple act of tumbling about is so monstrously enjoyable that Wiz and Waz's spaceship has its own playroom, which you can visit with Wiz between missions. Inside, the landscape shifts and transforms, boulders froth like bubbles, and new features appear as you encounter them in the single-player mission, so that Wiz comes to have a bomb dispenser, a swing, a cart, and so on as his brother discovers them on the various planets.

Criticisms? Go on, then. The 25 levels are short and sharp, and only a precipitous difficulty curve keeps you from getting through the whole game in a couple of hours. Much of SolaRola's longevity resides in your own perseverance.

However, persevere you will, because every second playing SolaRola is a happy second, and in its standout moments – dislodging a cluster of boulders and watching them cascade through the crater hole, or bouncing onto a wagon for the first time and coaxing it down a bumpy slope – you become speechless, restricted to blurting staccato phrases: "sitting with your handset/grinning maniacally/playing the best mobile game of the year."