It has more side quest compared with its previous game (Sun and Moon). It has a little more of story and the villain got a reason to hunt the Ultra Beasts rather that just being crazy of pokemon's beauty.

3 new beast pokemon were added to the pokedex, the legendary hunting was added also and the ultra wormhole is fun and makes a little easy to hunt a shiny but they are just a few pokemons could be caught by this method.