Yoshi Topsy-Turvy is not a very good game, but it is an interesting attempt. The sequel, should there be one, will probably be terrific enough to blow your forehead clear off. In the meantime, there is enough here for a worthwhile afternoon. More on that in a moment.

First, some perspective. It is now clear that Nintendo is serious about reinventing the video game interface. In release after release this spring, the company has eschewed the classic move-thumbpad-push-buttons formula in favour of a series of experiments.

We have controlled Donkey Kong the ape by pounding on bongo drums. We have blown into our Game Boys to play Wario's silly mini-games. We have drawn lines to protect Kirby, and we have drawn ramps for him to climb. Nearly every time we pull out our Nintendos DS, we are asked to do something we have not done before in a video game. Some of these experiments are triumphs and some are merely neat. But the overall thrust of them is clear: Nintendo is bored with buttons and joysticks.

If you read the enthusiast press you know by now that Nintendo's next home console, which is code-named "Revolution," is slated to feature a controller unlike anything on offer right now. Now, nobody has the slightest idea what that means, and certainly all the lips at Nintendo are sealed, but this spring's parade of touch screens and odd-duck peripherals and gyroscopic tilt sensors gives us plenty to speculate about.

Maybe nothing will come of it, and the Revolution will go the way of Sega's brilliantly experimental but slow-selling Dreamcast. Maybe the Revolution will be the machine that wins the hearts of all those people who find first-person shooters dull and Madden tough to grasp. Either way, all this variety is a nice thing in the interim.

Now, Yoshi Topsy-Turvy. Like last month's gem WarioWare Twisted!, the new game features a tilt sensor, which detects how you are holding your Game Boy and whether you are leaning it to the right or to the left. The sad news is that Topsy-Turvy is vastly less impressive.

Here is how it works. Yoshi is a small green dinosaur who lives on an island. Sometimes he hangs out with Mario. One day, the evil dinosaur Bowser imprisons the whole island in a pop-up book and turns all the little baby dinosaur eggs into apples. Nobody is really sure why, except that while Bowser is evil, he is not evil enough to, say, smash the eggs or set something on fire. On the spectrum of villainy, he is somewhere between Gargamel and the Purple Pie Man.

We control Yoshi. Our job is to set things right once again, using the classic tools available to the platform-game hero: running and jumping. Because we are Yoshi we also have a long tongue, which we can use to grab floating treats and appleized eggs. And because the game features a tilt sensor we also have power over gravity.

We move left and right and jump using the thumbpad and the buttons. There are many blank cliff faces in the game, which would leave the traditional platform hero helpless. But by tilting the Game Boy, we can change which direction is "up." Suddenly, running straight up a wall is easy. Whee! Sometimes huge boulders or snowballs block our path. We tilt the Game Boy and they begin to roll. Whee! We fall into the mouth of a cannon. We tilt the Game Boy to aim, and land precisely where we wish. Whee!

All these are very good ideas, but their execution is flat. There is never any mystery about how we should tilt the machine, so the novelty wears out quickly and the fun goes shortly after that. Also, the tilt sensor itself is vastly less sensitive than the one that came with WarioWare. It knows "left" and "right," but it doesn't do subtlety. Maybe they are saving that for Mario.