The difference between 89 and 90 seems so big lol
For every two games on Opencritic scoring 88-90, there is only one game scoring 91-93. And for every two games scoring 91-93 there is only one game scoring 94-96. No game has managed to score above 96 on Opencritic.
So yeah, the difference is pretty big, so long as we are talking about how difficult it is to get those higher scores. IMO 88-95 scored games are usually around the same ballpark in quality though.