Cheetahmen is an awesome unlicensed NES game series about a group of totally radical commandos who are also anthropomorphic cheetahs. The first game was absolutely the best game on the Action 52cartridge, and its sequel Cheetahmen 2 is, similarly, the best game on the Cheetahmen 2 cartridge.
Apparently, Cheetahmen 2 has become something of a meme in the Japanese Nico Nico Douga community, and we didn't even notice. We've been missing out on somuchfun! The music has become an "Okkusenman" like source of endless creativity. So much so that a full Cheetahmen 2 fan album was released at the latest Comic Market at the end of December. Sample snippets are available at the link, but suffice it to say that it's easily the best album based on Cheetahmen 2 that we've ever heard.