Had a play around with it last night. It's very good - very slick presenation. Managed to make a fairly straight forward seek and destroy mission in the cemetary with some non-target hostiles roaming around as well.
I've still not had a chance to play it luckily it downloaded before the PSN outage. Is it just making levels and uploading them or do you get to play them?
I managed to get most of it while PSN was up - so the creating side works for me. I made a mission and it works really well. It's even better when you watch someone play your mission and see them play completly different from you.