Not going through the Guardian Moon

Hi!
Can I proceed to Inside the comet level without going through the Guardian Moon. There is an error when I went back to get the remaining two gems at the Lonely Iceberg, thus not able to complete the rainbow road. Will it affect the ending of the game?
Awaiting for your reply.

Thank you!

I am not 100% sure, but I don't think so as finding all the gems (and thus doing Guardian Moon) is kind of an extra. All I do know for sure is that you can't go back to find the gems after you finish the last level.

You have to find 100% of gems to get access to the guardian moon. the guardian moon must be played because there are things on it that you need for the last level.