Portal technology - zipping you between two otherwise unconnected points in a level, even if you walk in through a wall and fall out through a ceiling - has been slowly leaking into shooters for years: the just-released Prey was originally announced in 1997 using the stuff. But it's the upcoming Portal - a Half-Life 2 side story - that should make headache-inducing reality-bending the new lens flare.
Given a gun that can spit a pair of portable holes (one in, one out) at whatever points you choose, you'll solve level design puzzles by thinking in 3D space instead of matching blue key cards to blue doors. So brainy that it doesn't actually have combat, we still know it's going to be a trendsetter.
Portal is coming in 2007 to PC, PS3 and Xbox 360
Above: Following yourself through your own portals is, worryingly, the least boggling action required of you in Portal