Valve has released a few details on the sequel to the much acclaimed Portal. According to Game Informer Magazine, Portal 2 will take place hundreds of years after the original in an overgrown Aperture science lab. GlaDOS will also be returning to antagonise the hero Chell.
There will be a split screen co-op mode where you assume control of bipedal robots and use physics and reactive paints to solve puzzles.
Portal was, according to Valve, a "test bed" whereas Portal 2 will actually be a fully fledged game. The game is scheduled for a summer release. A Mac version is promised for simultaneous release with the PC version.