stabbed in the neck: with a knitting needle in a not-aimed shot. I dunno how sharp those things are, but depending on where it hit, this is survivable
poked in the eye: his eyes look fine for the couple secons the mask is off of him. Probably didn't actually hit his eye
Stabbed in the stomach: not necessarily fatal
shot in the heart six times, fell out a two story window: Yeah, these are harder to explain, but mostly because of Halloween 2. Taken as a standalone movie, which was supposed to be the case, it's not out of the question.