Nah, that's not it. I did find it, though.
It's called Star Castle. The guy is D. Scott Williamson. He's got a page on Kickstarter for it.
I would link the page, but I'm currently on mobile web, and this Pantech turd can't copy and paste.
Google would pretty much take you straight there, anyway.
He is selling cartridges of it and I like the fact that the cartridge case is made of clear acrylic and he mounted an LED on the ROM so it lights up when you play it. Looks pretty sweet...
The story of how it came to be is definitely an interesting read, too.