6/10 for me. 4 of that is for bill murry. This could have been so much better and actually it did start off really well it just went downhill fast. If you havent seen it just watch the bill murray bit on youtube, save yourself some time sitting through the crap bits, i.e. the rest of the film.
It goes roughly like this:
0-10mins - amusing intro and killing a few zombies.
10-100mins - drive around talking with a few omg i didnt see that coming
moments.
100-110mins - Bill Murray bit.
110-end - killing a few zombies.