Go inside the project and put the SPRITES inside you backpack. The music is in the backdrop, you go to the [sounds] tab, open the backpack and drag "Bad Time Trio.mp3" into it. :D
Undertale by Toby Fox Underswap by Popcornpr1nce Storyshift by voltrathelively Bad Time Trio Game by MCatR Bad Time Trio Music by Elmauri Explosion from @BruceDee1
