Answer:
Some of the technology, the backstory, and organisms are not believable. Other than that, this world is believable. A dystopian government that forces each and one person from every district into a battle royale is realistic and possible. But technology in this world are not proven to be real in our universe. Also, there are also organisms in this world called "mutts" which is biologically unrealistic in our universe. Also, in the back story of the hunger games, the entire world went into a series of natural disasters causing the United States to shrink and start a dystopian society in the United States.