Julius Mode is awesome. It has an actual story, (it's just "Soma is evil and is hiding in The Abyss and the throne room at the same time somehow, go kill him. Oh and all the bosses are back for some reason." But it's better than nothing) three new characters, three new songs, and a new boss. It's a shame the alternate character modes in the other games are fairly lackluster in comparison.
Sorry, didn't mean to write a novel there.
This song is a remix of Beginning from Castlevania III.
This song plays in the Lost Village in Julius Mode.