In intellectual property law you have a few different concepts including:
- copyright
- trademarks
- patents
Copyright law would generally prohibit ripping off the original assets from another game or copying their code, but it would to my understanding not prevent anyone from making a “clone” of another game as long as the assets and the code are your own. And as long as those assets of yours are actually distinct looking and not the same look or too similar to the original, and your code is your own and not something you wrote by reverse engineering the code of the original yourself. Also there is a concept called “clean room implementation” that is sometimes used where they do reverse engineer other people’s code, but the person or people doing the reverse engineering and the person or people implementing the clone are separate people and the people implementing it only look at documentation from the people that reverse engineered it without looking at any of the reverse engineered code itself.
Trademark law might prevent you from using the name “Breakout” in the name of your clone, if there is a trademark on that. On the other hand, if there was a trademark but the name has become a generic word for the thing, the holders of the original trademark might not be able to prevent you from using the name even so. I have not looked into the trademark status of “Breakout”.
Software patents might prevent you from copying mechanics from a game. For example if there is a patent relating to how Breakout works. I haven’t looked into whether there are any patents on that, as I am not planning to publish any Breakout clone myself.
I assumed that the game was so old the concept was up for grab, but there might be some obscure patent. Given how many successful commercial games were made based on this concept, I'd assume the patent trolls would have killed the genre if there were any with valid patents to show. I might be wrong ^^
(Not buzzkilling anything, just genuinely curious.)