I beat the three levels about ten minutes ago. I've got mixed feelings. It feels very unpolished and the textures seems murky. Compared to RE5's demo, I'm not very impressed. I almost feel like RE5 looks and plays better, but that may be because I've played only a tiny amount of time. Also, I'm not sure I understand the over-complicated menus. Anyways, I'm cautiously looking forward Jake's campaign, because it was the one that seemed the most fun to me.
Overall, i'm still looking forward to purchase the full game but the demo didn't impress me.