Similar movies

That is a tough one! let me see...

2001- both have classical music

Braveheart- both are historical "stories" that won awards

Good Will Hunting - both involve geniuses

Most of the others just are similar because they are both well acted/written dramas.

Lust for Life (1956) would be the one I'd pick.

They are all Oscar winners ;)

The algorithm is just including movies that are also in the IMDb 250 top list

Is not a prefect system and happen whit every movie, if you look for let say matrix the list is gonna be similar you would find only movies thar are also in the 250 top list, i bet they add some variables like the people who give ten stars to Amadeus what other movies they give the same ten stars that also are in the list and things like that

The logic of the system is more about what people like, if you like this the others movies of the same genre or with the same general rating that you also like most be similar

That "Similar Movies" section comes up with the most bizarre recommendations sometimes. To pick a few movies from the list you quoted:

2001: apparently similar to Reservoir Dogs

Braveheart: similar to Forrest Gump

Good Will Hunting: similar to Saving Private Ryan

One Flew Over the Cuckoo's Nest: similar to GoodFellas and Schinder's List

The Shining: similar to Back to the Future

Here's a real list of similar movies...

Immortal Beloved

Girl With A Pearl Earring

The Red Violin

Marie Antoinette (2006)

Barry Lyndon

Valmont

I suppose most of the period pieces set in similar times will do. But finding a film that's almost exactly like Amadeus will be hard to do. It's quite unique.

Here's a list of other composer biopics by the way:
http://rick-heli.site/composers.html

I see some similarities to The Prestige in the sense that it follows two rival magicians rather than two rival composers and one of them is flat out obsessed with the other.