Excellent concept/subject! Lots of funny, which seems to be getting rare at the moment. This is very close to being ready for prime time.
Do a spellcheck and check your grammar. Use full sentences also; it helps to pretend this is Wikipedia. Also, the style is to not use all caps in sections and subsections just like in the article title, so it's "Early history", etc. and "The Big Bang reboot" unless you intend to write about something called "The Big Bang Reboot". There is a copy editor lurking, but don't expect him/her to clean things up for you before a couple of years has passed. I will volunteer to do a final check if you want -- spelling, grammar and syntax only.
You might condense some of the ACE subcategories into "Superheroes" or "Genre" or somesuch. Right now, there's too many subcategories of a few lines each for my taste. If you're truly stuck for a Marvel entry for Big Bang reboot/0ACE, just drop the section. If you have just a little more, it's better to expand the Marvel entry in ACE, I think.
It also helps tremendously to have a fairly big lead picture for impact, right up top. "Saving Private Elmo" might be usable there, but it is old news/a well known image unless you can cook up a really good funny caption. The current caption is tolerable, but you really want some kind of impact with the first image. If you don't Photoshop, it may be useful to have it worked on in the "request for image" page and see what you get. You don't have to use any result but it helps to be able to work with what you get if it's not crap.
The BCE section needs a picture. The ACE section has too many pictures close together for my taste. If I had my druthers, I'd drop the black picture, the weakest/easiest joke of the bunch. You can move up T-Rex Star Wars in position, so long as some of it touches the Star Wars subsection. It's best to get a flow of pictures to keep the reader going through the article, kind of like finding Easter Eggs.
The last section is good as it is. No need to expand this, really.
By tags, do you mean the internal links to other Uncyclopedia pages? If so, add at least some or go crazy. It lets readers find other articles and you can even throw in a couple of Rickroll-type links, but just a couple. If you mean references, some is better than none, so you're good to go.