New Updates In Minecraft 1.2.3

All the changes in 1.2:
Ladders regained their collision box.
Vines are climbable if you push into a solid block while next to them.
Added jungle biomes (requires a new world or new chunks) with ferns and new wood and leaf types.
Updated language files.
Dispensers dispensing Spawn Eggs will place Mobs instead of simply dispensing the eggs.
Spawn eggs are now stackable.
Zombies have new path-finding AI.
Wolves have new AI and can be bred using Raw Chicken, Cooked Chicken, Raw Porkchops, Cooked Porkchops, Raw Beef, Steak, or Rotten Flesh, when tamed.
As of snapshot 12w04a:
New jungle-specific Ocelot mob that can be tamed into Cats using Raw Fish.
Mobs in general have new a AI with new and improved behaviors.
Skeletons and Zombies burning from sunlight will flee to darkness or jump in Water.
Mobs no longer attempt to jump over Wooden Fences.
Mobs no longer attempt to walk over Signs or other non-solid Blocks if the drop below is too tall.
New Items:
Fire Charge
Jungle Sapling
Bottle o' Enchanting (Creative Mode)
Spawn Ocelot (Creative Mode)
Updated Language files.
Changed Dispenser and Oak Sapling textures. ()
Added Desert Wells.
Players are slowed when going through Vines due to their nature of being a collision-less Ladders.
As of snapshot 12w05a:
New Mob behaviors.
Creepers run away from Cats and also stalk players.
Cats can be told to sit.
Mobs no longer attempt to jump over Nether Brick Fences.
Villagers will try to detect village houses and live in them.
Villagers will roam around at Day and stay inside at Night.
Villagers are able to open and close Doors.
Lava now has sounds.
Ocelots are easier to tame.
Abandoned Mine Shafts now bridge over gaps in paths.
Enchantment Tables no longer require Experience in Creative Mode.
Updated Language files, having "50%" less profanities.
Redstone-related items can be placed on Glowstone Blocks again.
You can get Dead Bushes by using shears on them.
As of snapshot 12w05b:
Fixed shift-clicking the result from Crafting only giving one item regardless of the amount of material used.
Cats will now sit if right-clicked with an empty hand.
Death screen has a slight delay before buttons become active, to avoid accidentally clicking buttons when killed.
Survival MultiPlayer mob hitboxes are fixed, so they apply to the full mob, instead of only the head.[1]
As of snapshot 12w06a:
Many minor bug fixes and tweaks.
Creepers no longer explode after death.
Villagers can no longer open iron doors.
Cats, Ocelots, Zombies, Wolves, and Skeletons no longer spin in circles on non-full-height blocks.
Doors have been changed to properly detect if they are open or closed. Double Doors in existing maps will need to be updated.
Placing two Pressure Plates directly in front of doors and stepping on them will open them correctly.
When stepping on a single Pressure Plate only the door on that side will open.
When stepping on both Pressure Plates both doors will open.
Villager's AI has been improved.
Villagers socialize with each other and passive mobs.
Villagers go inside for shelter when it's raining.
Villagers run away from Zombies.
When a player aggros a hostile mob, it will continue to track the player despite being attacked by other mobs.
Zombie's AI has been improved.
On Hard difficulty and Hardcore Mode, zombies break down Doors.
On normal and easy Difficulty, zombies attack but will not break down Doors.
Zombies chase and attack Villagers.
Zombies attack doors when attempting to escape sunlight.
Added new sounds.
Cats meow, cry, howl, purr and hiss.
Doors make banging sounds when Zombies attack them.
Better movement for mobs in Water.
Mobs move slower.
Added rare Item drops for mobs.
Zombies have a rare chance to drop a Iron Ingot, Iron Helmet, Iron Shovel, or an Iron Sword.
Skeletons have a rare chance to drop a Bow or an Enchanted Bow.
Zombie Pigmen have a rare chance to drop a Golden Helmet, Gold Ingot, Golden Sword, or an Enchanted Golden Sword.
Pressing F1 disables hitbox outlines on blocks.
Monster Spawners now show correct mobs in multiplayer.
Snow Golems take damage from rain and water.
As of snapshot 12w07a:[2]
World format changed for the second time, conned "Anvil", with an automatic world converter from the current "McRegion"[3].
Maximum build height increased to 256 (was 128).
Empty sections of the world will not be loaded into memory.
Block ids increased to 4096 (is 256) by adding a 4 bit data layer (as of this snapshot it is only working for items).
Block ordering will be changed from x/z/y to y/z/x in order to improve compression.
Packets for sending chunks will be updated (a full 128-high chunk is smaller than the old format, and a chunk with lots of empty space is much smaller).
Biomes will be saved per x/z column, which means they can be altered by tools.
Light calculations in SMP take place client-side
Remaining animals were moved into new AI system.[4]
Added Redstone Lamp [5]
Decreased dropping chance for rare items
Villagers repopulate villages based on the number of houses
Zombies have a chance of attacking villages at night (part of the upcoming Sieges feature)
Villagers have children, which always sprint
As of snapshot 12w08a:[6]
Added Iron Golem, a new utility mob.
Defense for Villages.[7]
Removed some Canadian English stereotypes.
Multiplayer no longer says "Go camping with your buddies, eh?"
Added upside-down stairs.[8]
Many changes to the world and lighting system.
Lava ponds and flat stone areas generate on the surface more frequently.
Torches and Redstone torches can be placed on the top of Glass.
Fixed The End and Caverns generation.
Added sieges between zombies and villagers.
As of Minecraft 1.2 Preview:[9]
Added a new type of Stone Brick, called Circle Stone Brick, which is only accessible in Creative Mode.
Pressing F3 now displays what biome you are currently in. Also, raw, sky & block brightness values called rl, sl & bl respectively.
Slabs can now be placed upside-down.
Added mechanical sounds for Iron Golems
When crafting Slabs, you now get 6 instead of 3.
When crafting Ladders, you now get 3 instead of 2.
Two new blocks have been added to the terrain.png file. They look similar to Sandstone but instead they contain hieroglyphics. These blocks have not been added to game yet. ( , )