Update: It’s up.
Original: Ruffian Games and Microsoft are to release the Crackdown 2 demo later today.
The taster allows you to take part in four-player co-op, earn Demo Achievements and also gives accelerated leveling.
Demo Achievements in particular sounds like a great feature, allowing you to unlock rewards before purchasing the full game. We can see other developers copying that feature.
The demo will weigh in at 1.07Gb, and the game ships on July 9.