I just posted a devlog with some updates regarding the packs, check them out :)
Viewing post in Green Heart Base Pack - 16x16 top down pixel asset pack comments
Thank you so much for the help! Unfortunately, I'm still only seeing GHBP Demo V1.8.zip available when I click "Download". Wonder if itch.io is considering GHBP_Premium_V2.5.zip as a new file that I don't have access to, rather than an updated version of the existing file? (the version I had previously purchased and downloaded was v2.0)