Simplify the following text for a Grade 9 native English-speaking person.
Original: The Advance Wars series , known as in Japan as Famicom Wars , and often ( yet unofficially ) referred to as `` Nintendo Wars '' when referring to all the installments internationally , is a series of military turn-based and real-time strategy video games ( See wargame ) , usually developed by Intelligent Systems and published by Nintendo .
Simplified: The Wars series is a series of video games made by Nintendo that has appeared on many Nintendo systems starting with the Nintendo Entertainment System . Its first game is Famicom Wars , and it has a spin-off called Battalion Wars .