• Prismarine, Dark Prismarine, and Prismarine Bricks: These blocks are found in ocean monuments and can be crafted using prismarine shards and crystals. 

• Red Sandstone: A new variant of sandstone found in mesas. 

• Slime Block: A bouncy block that can be used to create interesting contraptions. 

• Iron Trapdoor: A redstone-powered trapdoor. 

• Granite, Andesite, and Diorite: New stone types that can be found in caves and crafted into smooth variants. 

New Mobs:

• Guardians and Elder Guardians: Hostile mobs that guard ocean monuments, with the Elder Guardian being a boss mob. 

• Endermites: Small, hostile mobs that can be found near endermen or spawned with an endermite spawn egg. 

• Rabbits: A new passive mob that can be found in various biomes. 

New Structures:

• Ocean Monuments: Underwater structures made of prismarine, guarded by guardians and containing gold blocks. 

Other Notable Changes:

• Revamped Combat: Hold-to-charge bows, critical hits, and attack animations for hostile mobs. 

• Hunger System: A new hunger bar that needs to be filled by consuming food. 

• Spectator Mode: A game mode that allows players to fly through walls and observe the world without interacting with it, useful for map makers. 

• New Commands: Several new commands, including /execute, /trigger, /replaceitem, /blockdata, /entitydata, /clone, /fill, /testforblocks, /stats, /worldborder, /title, and /particle. 

• New Achievements: Including "Kill a skeleton with an arrow at 50 meters