The director of the anime I think it was (you can check on this, the interview I'm talking about it quoted and linked in the show's Wikipedia page) says that the ending is open to interpretation as to whether or not Spike died. I mean...bullets go through his head, just watch the clip. he gets rekt HARD and I think the director or writer didn't want their OC to die so they tried walking it back in interviews and stuff. Either kill him or don't. If you want me to have an emotional reaction, your big cash-out moment can't be left ambiguous.