Back in 1988, Capcom was set to release Titan Warriors on the NES, a sequel to Vulgus, its very first arcade game.
Also known as Neo Vulgus, it boasts some truly amazing (and quite bizarre) sprite work and a fantastic soundtrack by Junko Tamiya.
Titan Warriors was featured in Electronic Game Player in 1988 before being removed from the release schedules entirely – it didn't even get a Japanese release (there's an excellent piece on the game here).
While nobody knows why Capcom pulled the plug on this one, but thanks to the fact that a prototype version exists, you can check it out via emulation or on real hardware using a flash cart.
While this build of the game is fully playable, it isn't final and may therefore contain some bugs.
It's certainly worth a look if you like your 8-bit shooters – and some of the visuals are brilliantly odd.