There is an issue with the demo. It doesn't seem to affect everyone but it is affecting quite a few. It's probably some sort of bug that only happens under certain conditions. The demo has been pulled off the EU PSN stores for now.
I just wish it had online, then I'd buy it right away. I'll wait for it to be cheaper to buy. I hope it does well though, it was rather fun from the demo. If I had someone locally to play with, then I'd buy it but I never have anyone to play with locally so I need online play or it's a solo affair.