The music of Little Town Hero was composed by one of the best musicians in the video game industry and Game Freak hid a way to listen to his songs in the title screen of the game.
The soundtrack for Little Town Hero was composed by Toby Fox of Undertale fame, which is his first collaboration with Game Freak. Fox also collaborated with Nintendo for the DLC in Super Smash Bros. Ultimate, as he created a remixed version of "Megalovania" that came bundled with the Mii Fighter outfit for Sans.
Little Town Hero had yet to be unlocked on digital storefronts when Game Freak revealed a secret about the game. A livestream was held to celebrate the 30th anniversary of the founding of the company and footage from Little Town Hero and the upcoming Pokémon Sword & Shield were shown. Little Town Hero was featured extensively during the livestream, as the developers counted down to it being officially released in Japan.
In order to listen to the tunes from the Little Town Hero soundtrack, the player only needs to press the L and R buttons on the Joy-Cons or controller while on the title screen in order to play a song. The player can select the previous song or next song by hitting L or R again.
The caveat to this trick is that the player can only listen to songs after they have heard in the game. This means that the soundtrack will gradually be unlocked as the player makes their way through Little Town Hero.
It's not uncommon for video games to include options that allow them to listen to the soundtrack of the game, as these are a holdover from the days when music menus were necessary for testing a game and developers would leave them in for the player to enjoy. Although the fact that Little Town Hero has such a prominent composer makes it a little surprising that Game Freak would want to hide the music player within the title screen, rather than putting it in a separate menu.