Hello, the mega bundle changes once a month, it doesn't include everything on my store.
Fanatical bundle includes music, tools and monsters which are not part of Fantasy Dreamland, the Fanatical bundle gives you a better price for the amount of assets included but you won't get new updates for Fantasy Dreamland unless you get the world pack here on Itch or on Unity.
You can find my contact on my website or twitter page, thanks!