Portal 2 splitscreen on PC?

Valve have released a patch which enables two-controller splitscreen play for Portal 2 on PC! And you aren’t restricted to squinting at a fraction of your desktop monitor, either as the update adds support for Big Picture mode. All you have to do to activate splitscreen is to press X on the second controller inside the first co-op menu, and then a whole new world of same-screen squabbling is available. The patch also fixes a couple of controller support glitches: previously the ‘quick ping’ button caused the player’s movement to stop and it was impossible to exit Robot Enrichment or Create Test Chambers menus using the controller alone. No longer!