It's not a singular fic, but it's a weird and ghastly mixture of bad sprite comic and badfic (though the writing is worse than the sprite stuff), the worst of both worlds. It's called "Simon Quest Zero", there's supposed to be some kind of prequel to it in the author's gallery, but I don't want to trudge through all his stuff just to find it. I haven't finished with this 'fic', but what I've seen is enough to say it's bad, I think.

Of course, it's good for a laugh anyway.

http://belmondo4447.deviantart.com/gallery/#Simon-Quest-Zero

In summary: An implausible crossover involving Castlevania and Mega Man, mainly, with characters from all over each series' respective timelines, but multiple other continuities appear from Pokemon to Zelda. The main focus of the plot involves one of the most crackiest crossover ships I have ever seen - Simon freakn' Belmont and Leviathan from Mega Man Zero. No, seriously. Plus, they have kids. Note that the female of the pairing is a Reploid, a very advanced robot, but a robot nontheless. Canon defilement up the wazoo, along with bad grammar and spelling and just bad writing overall. On the visual side, not much to charge for, aside from bad speech bubbles (even in MS Paint, one can easily do better). Oh, yeah, and particular part adds songfic to the list.

tl;dr: Badly-done crossover pairing fic that's crackier than crack and combines bad sprite comics with normal badfic. I'll give a better impression when I finish looking at the whole thing.

Also, Evil!Soma Cruz makes me grumble, but that's not really a charge.