That would grow tiring after 45 minutes of screen time, so Hart doesn't try to do the voice exactly, but rather nail the vibe of an old man getting a huge kick out of traipsing around a video game and suddenly knowing dozens of animal fun facts which he'll spout off at random. It's a tricky balancing act, and Hart succeeds, elevating his performance beyond just an impression of soft-spoken Glover.
Since the avatar he plays, weapons keeper and zoologist Franklin "Mouse" Finbar, spends a lot of the film inhabited by easy-going, talkative, retired restaurant manager Milo (Danny Glover in the "real" world), he has to act like Milo by way of Mouse. In Jumanji: The Next Level, Hart's screen persona is wildly different, because it has to be. Hart usually plays the same kind of character: ones that act and sound exactly like Hart does on stage. Kevin Hart is obviously a funny guy - the man's a professional stand-up comedian and he's made a lucrative second career for himself as a movie star.