Disc-based video games, the ones that cost $60 and come in a plastic box, may be heading the way of the VHS cassette and the eight-track tape. Many industry pundits believe that by 2020, if not sooner, you'll download all your games - just as you do now with music and smartphone apps.
Right now, though, the download-only market is still somewhat of a laboratory for game designers who want to experiment with new ideas. And no lab is wackier than the one you'll visit in "Quantum Conundrum" (Square Enix, for the Xbox 360, PlayStation 3, PC, $15).
Kim Swift, the lead designer of "Quantum Conundrum," was the mastermind behind the 2007 classic "Portal," and fans of that puzzle game will feel right at home. Professor Fitz Quadwrangle has discovered a way to switch among four dimensions with unusual physics. The "fluffy" and "heavy" dimensions make objects, respectively, lighter and heavier; you can also slow down time or reverse gravity.
In each of the rooms in "Quantum Conundrum," your mission is to use your primary tool, the Interdimensional Shift Device, to escape. For example, you may need to put a safe on a pressure-sensitive plate - but you have to make the safe fluffy to pick it up, then make it heavy to drop it on the target. By the final levels you'll be frantically juggling all four dimensions.
Quadwrangle, voiced by "Star Trek" veteran John de Lancie, is sarcastic but not quite as malevolent as "Portal" villain GLaDOS, and the jokes here aren't as sharp. But the puzzles themselves are every bit as clever. Three stars out of four.