Ok, if you aren't some sort of SNK enthusiast, bear with me here. Earlier this year, on April Fool's Day, SNK Playmore announced a game called Star Radish, an 8-bit Neo Geo shmup made by a "Mikadosoft." Everyone thought the game was a joke, but it's actually playable ... in Doki Majo Plus, a sequel to the notoriously NSFW Doki Majo Shinpan. Like the original, Plus is a witch-hunting game: players track down witches by looking for their "witch mark."
Except the witches are all junior high school students. And the "mark" is usually covered up by clothing.
In any case, one of the potential witches is a retro enthusiast named Renge Oda who will talk your ear off about games like Psycho Soldier if you let her. Enter Star Radish. I'm not sure how Doki Majo Plus makes the jump from "interrogating" Renge to playing her favorite new game, but it's there.
There's some gameplay footage after the break, but you'll have to sit through Renge's awful voiceovers the entire time, speaking some sort of moon-gibberish. The screen unexplicably goes dark at the 1:40 mark, though. Unfortunately, while it's a quirky bit of fanservice, Star Radish doesn't look interesting enough to sift through the hours of loli molestation required to get to it.