What is your favorite OBSCURE game?

If you plan to say Mario, Sonic, Duty, Halo, Kirby, Zelda, Mega Man or anything else that EVERY gamer has heard of, please think deeper and find something else unique that felt like only YOU played it. I want to actually look these up and try some. As a matter of fact, 360, PS3, Wii, and modern PC, BANNED. Give me an off title from last gen, including portable, to Master System and NES. (Don't give a **** about Atari and the like)