The movie is separated into 3 different time places, the child, the young and the old Beethoven. The movie started of amazingly, with astonishing acting by the child Beethoven. Also the cinematography and costumes/ sets are great.
Now to the bad parts: first of all the acting of the young, middle, Beethoven was unfortunately horrible and it kind of broke the immersion and made Beethoven look pretty dumb. But the most important part: the movie had a strong focus on the live of Beethoven but not the music. It was never shown how Beethoven wrote his great pieces, what the reception was, what influenced Beethoven's music. The movie completely skipped over the time periods Beethoven wrote most of his most iconic music. If you don't know the history yourself you are left kind of wondering why Beethoven was so popular in the first place since it is never shown. People only talk about him being great.
In my opinion, in a movie about Beethoven his music should be in the main focus, or at least some focus at all.