While this is a great idea with what is there, it's quite lacking in any in-game instruction and could use a few ways to interact with the other players. Off the top of my head the idea of making rituals that would mess with other players or enhance your own ability on the board would add a bit of strategy to the game, as currently whoever finishes first seems to win, so collecting runes and making rituals doesn't really matter - you can just ignore them all to roll.
Adding something like having rituals double dice rolls, steal rune stones from others, double the amount of the runes you get on your next landing, change the colours of your next runes to your desired colour, etc would add a bit more interest to the game beyond 'roll the dice, move, use some stones for no reason, move'. Also making the rituals themselves give points that factor in to the end result would be neat too - that way people can't just 'get to the end to win' and have to consider what kinds of rituals they want to make and use.
It would be more fun to be able to interact with the other players outside of making some music (and it would give a reason to make music in the first place if the rituals had uses). Personally I'd recommend having small sound combos for different effects, allowing maybe up to four to create an effect - thus allowing for two per ritual (since you only get a few chances to make rituals, it would limit people deliberately aiming to oversaturate their ritual potential while not damaging those who don't get as many runes as others from luck... if that makes sense.)
That said, the sound design is pretty good, as is the graphical design. Overall it's a neat idea that needs a little more to add some more interactivity between players and instruction of how to play inside the game itself.