The final two parts of Valve's seven-part trailer series showing their E3 2010 demonstration of Portal 2 are now available. In part six we are introduced to Repulsion Gel, which sounds like a common high school cologne, but in fact is more like grandson of Flubber. Part seven is about Propulsion Gel, which will help you run faster without having to resort to rockets from the Acme catalog. Part seven also concludes with some well wishing from an old friend. The clips are embedded below.