More there is not to say.
Or for the lazy ones:
To be fair though this quote here too so people can't complain.A video game clone is a video game or game series which is very similar to or heavily inspired by a previous popular game or game series. Some video game genres are founded by such archetypal games that all subsequent similar games are thought of as derivatives.
The term is sometimes derogatory, implying a lack of originality but clones can be anything from a pure "ripoff", to a legitimate derivative or improvement on the original or even a homage to it.