I've watched it only twice. Gonna go for a third ;)
I’m not sure if you remember exactly what happens in the movie at that point... but the zombie that Shawn and his mate where whacking “splattered” on Shawn’s shirt... if the movie wasn’t so funny, it would have been disgusting! But it’s definitely funny! :-)
I meant to mention as well... if you like Simon Pegg (lead actor in “Shawn of The Dead”, you’ll like “Hot Fuzz”. It’s also a hoot! :-) He’s the lead actor and his partner is the same guy who was his best mate in “Shawn of The Dead”.