it wasnt really the zombie coming back to life again, because if you blew its head of, or used the lighter fuel to set fire to it, then it wouldnt come back as a crimson head...(p.s top tip when playing hard, set every zombie you kill on fire, you dont wana come up against a crimson head when you have just a knife)
if its dead already think of it this way, taking a few bullets just slows it down, you have to do what any zombie horror suggests and burn it or blow the head off.
i personally loved this, it made you think twice about going round killing every zombie, watching a crimson head suddenly rise it, as fast as it does is scary as hell..the first time i was like wTFFFFFFFFFf paused the game and didnt un pause for ages lol.