I tried this numerous times on various levels and was convinced it was buggy as it just wouldn't pop for me. Then I found a single comment that suggested it wasn't buggy, just far more specific than the description implies.
Load up Episode 1 - Chapter 3 (Hell and High Water) in an offline game on Easy and start by killing the bots. Run to one of the gasoline puddles with enough zombies following you, set it on fire and stay standing in the puddle until enough have been killed by it
.Credit where it's due
Credit for figuring this out goes exclusively to a gamer called Heblon who posted a comment on this site...https://www.playstationtrophies.org/game/world-war-z/trophy/...
Here's the link to their own YouTube video showing exactly how it's done...Some Speculation
- That you absolutely do not need to read which is why it's at the end!
What I suspect
is happening here (and the reason everyone believes it to be bugged) is that the game is only registering the kill for those zombies that die either on contact with the puddle or actually in the puddle after a couple of seconds. If this is the case then the ones who run through, catch fire, stagger out and collapse don't count. Neither do the ones who run through, catch fire and then attack you while on fire before burning to (un)death. This would also lend credence to why some people report increased success rates doing it in a massive swarm such as Episode 4 - Chapter 2 (Final Call), simply because more zombies equals more chances for the specific criteria to be met...
Or I could simply be seeing a false positive because this worked for me first try after so many failed attempts and it is in fact, buggy as hell and it was nothing but blind luck that Heblon's method worked
. I don't think it was blind luck but I obviously have no way to prove it one way or another.