TGS: Echochrome

The idea is to "follow the echo", a little smoky outline that appears at different points along the solid white beams and pillars that make up the abstract levels, but you don't literally control your character - instead, you rotate the camera to change the rules governing the surfaces he/she/it is walking along, and in doing so the character's path is altered.

For example, the first rule of Echochrome is "subjective translation". Illustrating this is a snaking white beam that forms a sort of square-edged horseshoe that is higher at one tip than the other by virtue of a staircase in the middle. The idea is to get your little man to wander from one end of the beam to the other without jumping off, or doing anything acrobatic. The two ends are miles apart, not to mention at different heights. Impossible, surely.

Which is sort of the point. The way to do it is by rotating the camera with one of the analogue sticks until the end of the top beam aligns with the edge of the lower one. At this point the boundary between the two disappears, joining them even though in reality they exist at different heights. The camera turns lies into truth.

There are four other rules that you're able to manipulate by changing the camera angle. Position a beam with a black hole in it above a solid beam and your character will fall through it and land on the lower beam. Again, when you're first shown this the hole and the beam don't align at all - in fact they're on opposite sides of the framework. This works in reverse too, as white circles act as bounce-pads, allowing you to land on beams that are high up and off to one side by using the camera to bend the rules.

Another example of eliminating gaps is pushing the camera down so that a beam with a black hole in it cannot be seen from above, which renders the hole non-existent. You can do the same for gaps between adjacent beams - align a vertical beam so that it occludes the gap and it's as if the gap isn't there. This example probably sums up the concept of Echochrome better than the MC Escher references and optical illusion labels - gravity and physics do apply, but they're at the mercy of your current perspective.

It's as though you're rotating the level architecture, but your character doesn't reposition himself to reflect any loss of balance, which adds a mysterious quality to videos that's soon alleviated by actual hands-on.

Not that that's to diminish the game's attraction, mind you. The TGS demo ends with an actual level, which calls all your new skills into action. Twisting the world around like a snow globe, you get your character to fall, jump and walk unmolested around a network of beams that would be impossible to traverse under other circumstances. At the peak of its difficulty, you have to make the mental jump to drag the camera round sufficiently for the end point to tower over the start, even though it actually sits well below it. The little buzz of achievement you get from catching on to the world's logic is reminiscent of success in Valve's upcoming puzzler, Portal.

Best of all, it's not hectic or overwhelming at all. Your character only falls off if you misalign a jump or black-hole drop badly, moves at a reasonable pace, doesn't fall off the end of a beam (he just turns round and walks the other way), and strolls to the gentle accompaniment of a string solo. Armed with the knowledge of the concept-by-concept introduction levels, and a shoulder-button modifier that allows you to switch between fast and slow camera rotation, it's remarkably accessible.

For something which - by rights - should make absolutely no sense at all. The full thing can't come soon enough.