Giles is in the library, and his glasses repeatedly disappear and reappear between shots.
Kane uses a Bunsen burner with the collar closed (cooler, yellow flame) to melt the silver for his bullets. Even allowing for cinematic time compression (so that we imagine more time passes than we actually see between him putting the crucible in the flame and pouring out the molten silver), raising that much silver to its melting point of 962C with a small burner fueled by camping gas would have taken far too long for him to have sat there patiently holding the little crucible on a stick that he uses, especially when we see just how many bullets he appears to have made in this session (they're all set out on the work bench).
Giles notes he has enough PHENObarbital to sedate a small elephant. Phenobarbital is an anticonvulsant. PENTObarbital is a sedative.
Werewolf hunter Kane states he kills werewolves to obtain their teeth and pelts. However, in all other Buffyverse lore it's established that werewolves revert to human form upon death.
That would mean that Kane would have to pull their teeth and skin them while keeping them alive.
That would mean that Kane would have to pull their teeth and skin them while keeping them alive.
In gym class, Oz, Buffy and Cordelia have all failed to remove their earrings and at least one boy in the background is wearing a ring.