From the site:
Master the music
Get into the gameplay groove with this bundle of hit rhythm games! Toot to the tune of the smash indie phenomenon Trombone Champ. Embark on a rocking adventure to end the EDM Empire in No Straight Roads: Encore Edition. Fight to the beat in the fast-paced dungeon crawler Soundfall. Get a pulse-pounding playlist of great games, and help support First Book with your purchase!
Project Arrhythmia
Disaster Band
Tier 2 (£9.62) adds:
Trombone Champ
Soundfall
Melody's Escape 2
Tier 3 (£12.83) adds:
Beat Hazard 3
No Straight Roads: Encore Edition