I have a very specific tactic when it comes to reviewing games like this.  I show them to my girlfriend, then time how long it takes for her to let me back on the computer.

The last time something like this came along, it was World of Goo's original PC release last year.  Then, the results were telling.  It was the next day.

Crayon Physics Deluxe enjoyed a more modest reaction, and I'm surprised.  It's the same sort of charming, independently-created, physics-based puzzle-em-up, and the two share a few thematic parallels.  Here, the aim of each level is to reach the end-point - in this case a yellow star - by propelling a ball across some sort of course.  Which you draw yourself.  And utilise to make the ball move. 

It's very clever.  The original concept was fielded some time ago now, in the guise of the original Crayon Physics.  Developed in just five days, and inspired by the 'Experimental Gameplay Project' in which amateur developers create an original, playable concept in less than a week, Crayon Physics enabled only simple shapes to be drawn and, as such, very little variety was permitted.

Here, it's a magical playground of opportunity.  On top of the ramps and weights of the original game, all manner of creative systems can now be employed to drag your ball from A to B.  Complex pulley systems are particularly brilliant.  Creating a hinge then drawing an enormous foot to kick the ball beyond an obstacle is equally hilarious.  There's an abundance of different ways to catapult the ball across chasms.  You can even draw a box around the ball, attach the box to a rocket, and fire it into oblivion.  It's lovely.  I can't get enough.

Crayon Physics Deluxe primarily rewards imagination and creativity.  It's not a game for pure completists.  Until the final couple of chapters, there are only a few puzzles that require enormously complex solutions, and it's occasionally a little too tempting to work out the easiest solution and jump on to the next level immediately.  This isn't necessarily a criticism; it just requires you to alter your perceptions of how a puzzle game should be played.  Each level has an almost infinite array of options to choose from, and the unadulterated joy of playing Crayon Physics stems from challenging yourself to think of new, unique methods and paths.  There are a few occasions where it's simply too easy, and it begins to smack of poorly-planned level design.  One level in Chapter 2, for example, has half a pulley system set up for you to experiment with, but it's entirely possible to draw a straight line between the ball and the star and be done with it in a few measly seconds.  If there's an obvious problem with Crayon Physics, it's that, while it certainly rewards personal expression, it doesn't always encourage it.

Later levels, eventually, become fiendishly challenging.  I'm glad it's not always necessary to complete every single arena in a chapter, because if it were, I'd be stuck around two-thirds of the way through.  It's on these occasions that Crayon Physics really comes into its own, requiring careful thought, logical consideration of the exceptionally accurate physics, and a devilishly creative imagination.  When your Magical Robot Conveyor-Belt System (patent pending) whisks up the little red ball, catapults it through the air, catches it and plants it neatly on the other side of the castle, it's difficult not to let out a little squeak of joy.

It looks beautiful.  The innocently simplistic crayon outlines sit side-by-side with bizarre creatures and odd contraptions, littering the backdrop.  The music is breathtaking.  It sounds like a mixture of Samorost and World of Goo, but quainter and more blissfully relaxing than either.  I don't think I've smiled this much while playing a game since... well, ever.

I can understand the obvious complaints.  It does fluctuate between too easy and too difficult, it isn't always brilliantly designed, and the simple structure won't be everyone's cup of tea.  My girlfriend grew bored after just a couple of hours, handing the reigns back to me to create my own whimsical little world.  Maybe my system isn't foolproof.  But if you let yourself become absorbed in the way it wants you to play - that is, experimentally and wildly - Crayon Physics Deluxe becomes an adventure playground of infinite wonder.  I really like this game.

Somewhere within the combination of the invigorating main game and the wonderfully intuitive level editor - complete with the ability to share your creations online, Little Big Planet-style - lies a subtly ingenious creation.  Perhaps it lacks the narrative drive and the unquestionable polish of its main competitor.  But, like it, it oozes a certain compelling magic that's difficult to resist.  Even if it's not quite as remarkable, it's certainly the most charming game I've played since World of Goo, and both go to show you don't need enormous budgets and huge teams to create a masterpiece.

What a coincidence - look what's just come out on WiiWare.  Show the little guys you care, and buy both these wondrous games immediately.