Hey Tinkergnome,
The zombies shouldn't be droping bullets before the tutorial is over but I have noticed that if people use the Ammo cheat during the tutorial it breaks the part where it tells you to shoot the bottles. I'm trying to find another really game breaking bug to fix this because exporting to all the platforms takes a really long time,
I will fix this before the next update, hopefully we can find something else to fix along with it,
Thanks for the feedback and support,
Rafi