SEXY PARODIUS / Konami / Arcade
Many people think of Parodius as just being the one SNES game, but a few arcade games were released in Japan too. I think Sexy Parodius was the last actual game before the IP started just being used for a line of like 10000 pachinko machines.
Anyway, if you're new to the party, Parodius is Konami's little self-parody of Gradius and their other shooter games. "Sexy" Parodius is sexy becauase it apparently centers on the perverted dreams of Hentai Octopus or whoever that guy is. I didn't see any outright nudity, but there's lots of cheesecake throughout.
Sexy Parodius doesn't make it easy to access its sexy, goofy shooter fun, however, because it's balls hard. It's heavily memorization-based, and particularly relies on you getting the right power-ups at the right times (and then holding onto them for a long, long time.) It's also one of those arcade games you can't just power through by spending money, because it has a checkpoint system. If you die right after certain checkpoints - like right before a boss - you might as well just let time run out and start over from level 1. I think the idea is to hoard up all the good upgrades in the relatively tame level 1, then basically try to not ever die after that.
Good luck with that strategy in level 2, a really assy high-speed auto-scrolling level that also forces you to collect X amount of coins. Die at the wrong checkpoint here and you're basically totally fucked. You're not only expected to memorize the level to survive but you'll also need upgrades to get through certain points unless you're some sort of autistic savant.
I don't know if Konami made this intentionally frustrating to keep kids pumping in quarters to see the "sexy" content, but whatever the case, it's a neat shooter with nice graphics and a lot of great ideas that's really held back by poor level plotting and just generally being too demanding.