#1 I think you need a margin-bottom for class .post_footer and I wouldn't be afraid to make it quite a chunky gap, perhaps 40px or so.
Currently the dates are two close to the items below. At first, I thought the dates represented the subsequent posting, rather than the previous one.
#2 It seems you have default Times New Roman font in the footers. It makes me think of basic mid-nineties sites.
#3 Your pages flex, because they are centre-aligned. So when you move to a page with no vertical scroll, your page darts slightly to one side to make use of the extra room. Maybe using html{overflow-y: scroll;} would be better.
#4 Also, just a thought (and this may actually be a bad idea), you could have your rating buttons as blue/orange. Red and green don't go with the blue/orange.
Of course doing that may confuse users about the difference between "good times" and "good story".
#5 "No stories match your request. Be the first to make one!" - perhaps make this a hyperlink to the submit story page
#6 I think the ?retro links should not clear down the ?vice selection and vice-versa
#7 Maybe link to related stories from the story page. either by keyword association or just simply a selection of stories with the same vice/retro - this would improve SEO, as you'd have better associated linking
#8 Have an RSS of the stories.
You might be best using something like Wordpress with your own custom theme, as it will do a lot of the SEO/RSS things for you. It's not too difficult to customise Wordpress to not look like a Wordpress site; especially when you are not using many of the features.