During the Nintendo Treehouse: Live @ E3 stream, a gameplay demo of Yoshi's Woolly World revealed some new details. The presentation unveiled a boss fight not available in show floor demos, which you can watch above. It was stated that the game's sound design struggled deciding on which instrument to prevalently feature in the game's score, but settled on acoustic guitar, which he needed to take lessons for as he was used to creating music digitally. The game features a casual Mellow Mode that offers stress-free gameplay. Collecting beads increases the number of bonus abilities Yoshi has in this mode. The developers created the game so it can be enjoyed in many ways.