The first time I saw Space Giraffe, I didn’t realize it was an excellent game. Jeff Minter was showing it off at the Game Developer’s Conference, and it looked just like Tempest, except you could push guys off the top of the web sometimes. And Jeff kept saying it wasn’t Tempest. But he was not sufficiently able to communicate to the audience why the game was interesting (which I verified, through several conversations, after his lecture. People pretty much thought it was just Tempest with some psychedelic stuff).