But should really, really, really bad deeds keep you out, no matter what? I don't care much for a God who says "just drop my name at the door, and they'll let you by." What's the point of the afterlife if it isn't about people getting their just desserts?
i guess that depends on what you think a really really bad deed is. according to the bible, no sin is worse than any other. it is only humans (arguably, in a selfish attempt to imagine oneself as more righteous than another) who gradiate sin. is being responsible for the murder of an entire race worse than lying to your spouse? i don't think so. and besides. there are plenty of races that were entirely (or almost so) wiped out in north america that no one even pays any attention to. for one, the mandans. those that were left were absorbed into other tribes. why? because they had blue eyes and might be confused as being human.
then you have the really not-so-bad things. like lying. what if your little lie causes something big and bad and nasty... say you're 'spending the evening' with your significant compatriot and and you lie so your parents won't be angry all over you. but you turn out to be that person's only alibi and he unjustly goes to prison (or worse) for something he didn't do, but you're still afraid that your parents will be mad at you. what then? yes it's a touch (excessively) farfetched, but you get the idea.
the only just thing is to assume that all bad things are equally bad and that the only thing that can save someone is a single specified method. there is either light or absence of light. there is no middle. a shadow is touched by ambient light. thus it is in the light.