Indy's sidekick delivers plenty of iconic lines throughout the film, proving to be effortlessly hilarious in each and every delivery.

Source: https://www.cbr.com/funniest-indiana-jones-movie-quotes/

More of Indy's personality and history are revealed in the film, allowing for the kind of character changes the previous installments lacked.

Source: https://screenrant.com/cast-indiana-jones-last-crusade-where-they-are-now/

Mutt was an interesting foil in theory -- the young rebel to Indy's stuffy teacher.

Source: https://www.cbr.com/indiana-jones-dial-of-destiny-what-happened-to-mutt/

Raiders of the Lost Arkspawned two more films in the '80s, Indiana Jones and the Temple of DoomIndiana Jones and the Last CrusadeThe Young Indiana Jones Chronicles was created, documenting Indy's younger years.

Source: https://screenrant.com/indiana-jones-franchise-streaming-disney-plus-movies-tv-show/

To be sure, Henry falls back into calling Indy Junior once they escape the collapsing temple, much to Indy's annoyance, but this is likely a force of habit on Henry's part.

Source: https://screenrant.com/indiana-jones-junior-nickname-dislike-true-meaning/