The second chunk of Portal 2's three-volume soundtrack 'Songs to Test by' is now available to download for free, bringing another eighteen toe-tapping tunes to your ears.

Accompanying the new soundtrack volume is another round of Portal 2 ringtones in handy Android and iOS formats. Some are based upon soundtrack snippets, whilst others simply in-game sound effects for your telephonic tililation.

Download the second iOS ringtone pack here, and the iOS sound effects ringtone pack here.

Download the second Android ringtone pack here, and the Android sound effects ringtone pack here.

Free Portal 2 downloadable content is expected on all platforms this summer, though this was announced in April and we've heard little of it since; who knows what degree of Valve time dilation is in effect? However, free DLC has been released for players using the fancy Razer Hydra motion controller, introducing a number of new mechanics.