Valve has released an extended co-op trailer for Portal 2, originally shown at PAX.
The GLaDOS-voiced footage features various co-op antics from the two robot chaps who’ll be the playable characters in co-op mode. GLaDOS appears to be banking on them having no discernible emotions, but the video shows them clearly displaying empathy, fear and affection – so that may end up causing something of a problem.
Towards the end, GLaDOS alludes to a mysterious “real purpose” she has planned for the duo which will make all of their prior testing worthwhile.
View the video, below.