Straight off the bat, soon as I'm seated in Nintendo's cosy demo room, I'm told that Mario Galaxy 2 is largely comprised of ideas 'left over' from the first game. Concepts and quirks which just couldn't be squeezed into the original Galaxy's cavalcade of moons and planetoids.

For nearly any other series it would be a resignation, an admittal that this is a B-side, destined to dwell in the shadow of its elder sibling. But when it comes to Nintendo's flagship character it's a cause for celebration - a chance to take another peek inside the ideas factory which produced the wonderful charm and variety of Super Mario Galaxy 1.

Pretty soon, I'm immersed in a chunky, primary coloured-world which delights and surprises at almost every turn. These are not what you could ever call leftovers in any ordinary sense; here are ideas which would keep other series running into double figures, casually tossed into the digital ether like bright confetti.

It all starts on a space ship. This time, instead of leeching a ride from Princess Rosalina, Mario has his very own galactic craft, ingeniously codenamed Starship Mario. Which, because it's a little planetoid complete with atmosphere and foliage, looks more like Luigi. Nevertheless it makes for a snazzy place to rest up between excursions into the cosmos, gradually becoming populated with various members of the extended Mario roster as you explore the universe and meet them.

Bumbling around on this most egocentric of spaceships serves as a quick reminder of Galaxy's system of gravity and perspective. This gives me a chance to reacquaint myself with the basic spin and ground pound attacks as I terrorise the glutinously chipper Toads dotted around the surface. Then I'm whisked off to one of SMG 2's early levels, a gentle learning curve galaxy known as Puzzle Plank.

Puzzle Plank is what would happen if you crashed an Early Learning Centre into a B&Q in space. It's full of brightly coloured wooden blocks, ground-poundable pegs and swishing buzzsaws - these chop away sections of the platforms, dropping you into the void. Fittingly, it's a slightly slower-paced area, asking a few questions of the old head muscle. In one instance those poundable pegs protruded from both sides of a surface, creating adjustable platforms which had to be stomped appropriately to reach the teleporting star for the next area. Towards the end, a familiar nemesis made a fresh appearance: say hello once again to the sliding block puzzle.

Normally even the suggestion of one of these frustrating toys is enough to get me stropping in a corner, but the wonderfully tactile, 3D approach which Nintendo has taken had me beaming. Instead of a flat set of tiles which have to be shuffled endlessly around to reveal a picture of something inane like a ballerina poodle playing a trumpet, Galaxy's sliding blocks are floating in the azure, with pounding points indicated on the outside edge. Pound these in the correct order and the whole thing slips satisfyingly into shape. It's as innovative and tactile a solution to an old problem as you might ever need.

Next up in our demo session was Boulder Bowl, a harsher environment of bare volcanic rock and sticky tarpits, populated by rock-spitting mushrooms and the venue for my first boss encounter. It's in Boulder Bowl where you will also come across one of the new power-ups for the first time, the less-rebellious-than-it-sounds Rock Mushroom. This flinty fungus swathes Mario in stone, granting him the power to curl up and roll around with a shake of the Wiimote. Doing so turns our hero into a thundering sphere of rubble, crushing most enemies and exercising a turn of speed. The rolling dash can also be used to clear obstructions and shatter rocks or crystals to reveal goodies. Plus it can be used, as I quickly discovered, to knock down the safety barriers on the edge of planets and tumble to a slow death in the vacuum of space.

In true Nintendo style, it's a mechanic which is quickly used for purposes of playfulness as well as practicality. Before long, after a quick ring-fenced scenario crushing some itinerant meanies, a hugely tempting ramp appears over the horizon, prefaced by a set of querulous ten-pins.

Striking through these and over the ramp spins me through one the series' trademark dizzying shifts in perspective, following Mario as he soars, arms akimbo, towards another distant moon. But wait, that's no moon - it's made of girders for a start, and it's inhabited by a giant, fuzzy blue armadillo. Darth Vader eat your heart out.

Rolladillo is pretty much what you'd expect, judging by both his name and his inclusion as a boss in a Mario game. He trundles around his little planet, attempting to crush the hero with just enough poor judgement to expose his fluffy blue bottom when he overshoots the mark. When he does, it's time to break out the new power-up and slam his booty with a quick boulder-roll. And what a lovely booty it is - covered in the oh-so-cuddly fur effect which made the first game's queen bee so charming.

With Rolladillo dispatched to the chemist for a family tube of preparation H the demo moves on to the delightful Cosmic Cove, probably the prettiest of all the environments being shown. It's a water level, and the mechanics of swimming, including the air gauge and the underwater bubbles which refresh it, return. It's a different world in the aquatic element, slower and less precise, requiring less twitch judgement and a bit more forward-planning. That is until you hit the giant switch up by the elderly penguin hanging around on the surface. Quick as a flash the water is turned to ice and, in a way which looks like it'll define the series, one environment quickly undergoes a costume change to become another challenge entirely.

Stepping out onto the frozen surface of the lake allows Mario to ice skate. He glies elegantly across the frosty waves, pirouetting when he jumps like a slightly butcher Billy Elliot. It doesn't have a massive influence on the gameplay - there is no speed skating mini-game or ice dancing to be done, but it's fun, and a perfect example of the sort of throwaway idea found throughout the game.

Next up came two old favourites, and another new toy: the ghost-house environs of Haunty Halls, Yoshi and the bulberry. Yoshi is just the same as always, appropriately untouched by evolution. Tongue grabbing is done via the pointer and Wiimote trigger, and his trademark flapping float-jump saved me from certain doom more often than professional pride allows me to disclose. The bulberry itself isn't an entirely new idea, but is reworked with that classic Nintendo charm which pardons a little plagiarism.

Essentially it's a torch, and the circle of light which it projects when Yoshi eats it gradually dimishes with time. This being a Boo level, there are some decidedly suspect engineering decisions being made in regard to structural integrity - there's scarcely a floor without holes. Some of these floors are also suffering from something of a Schrodinger-esque existential crisis - until they're illuminated by the bulberry they remain staunchly non-existent. Cue a frantic five minutes rushing from one glowing fruit to the next through a winding maze of sudden drops and dead ends, as the vital circle of light around Yoshi shrinks and shrinks. Definitely the most fun I've ever had in a haunted library with a dinosaur.

The last galaxy we saw, Honeybloom, marked the return of one of the first game's big favourites - the bee suit. Depicted in the side-on, 2.5D style which the camera occasionally switches to, this colourful zone is all flowers, grapes and fuzzy bee soldiers. Picking up the flight-enabling bee-suit early on, Mario putters his way around the exterior of a summer-green cube, resting on carnivorous flowers and little fluffy clouds to recharge his flight gauge.

All this amounts to a tiny slice of what the final game will have to offer, I'm told. As with the first game, nearly every level in Mario Galaxy 2 will feature multiple stars, subtly shifting the goals and structure of each galaxy each time. The comets also return, albeit in a slightly different form - the collection of each medal unlocking a specific challenge for each level, such as the need to complete it without taking damage.

Although the precise number of levels is being kept under wraps for now, the sheer depth of variation already on show bears witness to a playing field of real diversity. Super Mario Galaxy 2 feels fresh yet familiar, challenging yet charming. It's a game for anyone with an ounce of soul left in eyes tired of staring down sniper scopes and iron sights. The toybox beauty of this sequel, its aesthetic appeal and prismatic hypnotism, have charmed all over again.