In Raspberry Flavoured, some content from vanilla Minecraft has been changed and removed due to balancing reasons and personal choices.
Villages
Villages, Villagers, Illagers, Pillager Outposts and Patrols, Wandering Traders, and other related features have been removed. There are some remnants of their existence, like golems, and various rare artifacts.
Cats
Notably, the removal of villages changes the process of obtaining cats. Cats can now be obtained either by finding a natural spawn in a Witch Hut, or by getting an Ocelot to trust you by feeding it fish, and then feeding it cat food to convert it into a cat.
The Nether
The process of traveling to the Nether has been changed. While a portal frame is still constructed of a minimum of 10-14 Obsidian in a 4x5 shape as normal, it must be lit with Dimensional Tears. Dimensional Tears can be obtained by using a Glass Bottle on Crying Obsidian, and alternatively by killing Witches or looting their huts.
Crying Obsidian can be found in the Overworld at ruined portals. These ruined portals can either be discovered naturally, or intentionally sought out by crafting Awoken Exopearls, which will fly towards the nearest ruined portal structure in the same manner as Eyes of Ender.
The End
The End has been entirely removed, with some of its content altered to fit new themes.
Shulker Boxes
Shulker Boxes in Raspberry Flavoured have been re-named and re-themed into Terrabins, crafted with Turtle Scutes and a Soul Bead. For early-game and mid-game inventory solutions, Bundles serve the purpose of being able to pack together multiple types of items into a single 64-stack slot, while Sacks are essentially lesser Terrabins with 12 slots. Additionally, Bundles, Sacks and Terrabins' contents can be scrolled through in the inventory using the mouse scroll wheel.
Endermen
Endermen have been re-themed to Exokin. Their mechanics have not changed, only their visuals, name and home. More will be revealed in future updates.
Experience & Enchanting
Experience has been entirely removed in Raspberry Flavoured, and with this, enchanting has been revamped. Enchanted Tablets can be created in the Forge, which can be applied to armor and tools in a Smithing Table.
The enchantments that remain in Raspberry Flavoured are intended to be less "one size fits all", to encourage choosing the enchantments that fit individual players' play-style the best and considering what innate abilities some armor and tool materials possess as well.