I adore our classic castle/fortress/boss mixes a lot but the lack of 64 songs (remix or rip) is really surprising.
It's just Main twice (Brawl's rip, the new remix) and Slide twice (Rainbow Cruise, the rip).
Peach's Castle & Princess Peach's Castle don't even remix a Mario 64 song specifically they just remix the series' ground theme.
Sunshine is technically worse (2 Delfino Plazas and Ricco Harbor) but you really would think Mario 64 would have more. Just a really weird hole in the mario song line up considering it's such an iconic game