If you downloaded PS Vita firmware 1.69, which released this week, and tried to play the Escape Plan demo, you may find it's not working. That is what folks are reporting on the EU and US PlayStation boards, anyway.
This seems to be par for the course with firmware upgrades, where one regularly comes along to mess something up. This is a fairly benign example by all accounts, but just in case you've been trying to play the demo and can't, this might be the reason. You'll have to hang back and wait for Sony to fix it.
Firmware is videogames, guys. Firmware is so videogames.