Also, IANAL but Space Invaders is owned IP. I have no idea the legality of a blog post describing steps to create and releasing an existing game, but I've seen headlines on HN of engs in trouble for things I would not expect to be problematic. Maybe Space Invaders is in q-tip/band-aid territory at this point?, but if this was Zelda instead of Space Invaders, I could see things being more dicey.