Bioshock Infinite is a great shooter. it's story is good enough to keep you focused. The weapons and everything that ties in with that are generally great. It does well to keep the flame burning of the series.
Characters are very interesting and the plot keeps one engrossed. It can be scary - as expected. It's in everyway as good as it's predecessors. It's gameplay is not hard but not easy. It's never frustrating or asks questions.
Overall it's within the 8 bracket. 9 is too high for Bioshock infinite. The enemies keep you on your feet, the items fascinate you. The story constantly grasps your attention.