a) it had a really troubled development, spanning about 30 years, with several different companies holding the rights to it at once and
b) some scenes are technically amazing, with use of geometry and incredibly complex designs.
These gifs are mainly from the end sequence, when the big scary army of baddies invades. Every single frame was drawn by hand.
This is the Recobbled Cut, compiled by a group of fans who had access to storyboards and animatics, and most scenes have been faithfully restored/touched up as well.
Fun fact: in one of the released versions (not the one shown above), Matthew Broderick (Adult Simba) voiced the main character, Tack- who was given actual dialogue, and apparently songs were added as well.
(spoilers- read after you've watched the movie or if you're not going to)
Spoiler: show