This is one of those feasts where the Christians ‘assimilated’ the bits of paganism that they liked and made their own thing. Hallowe’en still very closely matches a pagan-type feast. However, other people know more about that than I do.
For me, Hallowe’en is when we are getting ready for All Saints, and we drive away bad things, such as ghosts, ghouls, witches, devils, and things that go bump in the night. I think there is a place for that in Christianity. We didn’t do anything this year, as we were not at home, but next year I hope to make a Jack-o-Lantern out of a pumpkin and pumpkin pie out of the rest of the pumpkin (because I like pumpkin pie). We do not do trick and treating, however, but that is because we don’t bother. Children who come to the house might get given sweets if we have any (I wouldn’t buy specially) or, more properly, fruit, as I think a nice apple is the proper thing to give.
Food: apples, pumpkin, pumpkin pie, specially decorated biscuits, etc.
Decoration, dressing up, parties: scary things: the idea being to be more scary than a scary thing and so scare it away.