Hello and Welcome to the Aperture Science Enrichment Center.
A few months ago Valve announced the second part of Portal as a full length experience and already delayed it's release to 2011. A few weeks ago Valve cancelled their Portal 2 show at E3 2010 in a GLaDOS-style letter. She did it again. She Lied.
Here is the first Teaser ...
... and a gameplay demo in 3 parts shown at E3.
Valve included a bunch of new features, enemies and helpers.