Official changelog is non-descriptive (“Censored” and “Some improvements”).[2]

* Enchanting requires no level in creative mode.
* Stackable items now stack outside inventory when thrown to the ground individually.
* "Pick Block" button now gives the correct block when used; when clicking on a mob, it gives the appropriate spawn egg.
* ⇧ Shift+clicking can be used to wear Armor.
* Brewing stands allows use of shift clicking to put items in it.
* Dispensers will deploy boats on water, and minecarts on rails. Powered minecarts and storage minecarts are also deployed similar to minecarts.
* Iron Golems now have sounds
* Right clicking a powered minecart in creative mode will act as if you would give it coal.

Notable Bugs:

* Pick Block :
o Several entities and blocks are currently unsupported by Pick Block and cause the player to crash if they attempt to Pick Block them. These include extended pistons, Ender Dragons, and other players.
o Pressing the Pick Block button on Redstone Dust gives you a Redstone Wire
o Pressing the Pick Block button on Long Grass gives you a Dead Bush placeable on dirt.
* Spawn Eggs now spawn baby mobs.[3]
* Baby mobs spawned in the above way will follow any adult of their mob type.
* Destroying floating sand may crash Minecraft.[citation needed]
* Changing the GUI scale will cause the game to crash.
* When Spawn Eggs are stacked outside the inventory, they will all become one type. If for example the player places eggs for squid, zombie, slime, and blaze on the ground and they stack, they may get 4 squid eggs back. The same bug occurs when multiple colors of wool blocks are stacked outside the inventory, causing them all to change to one color. This may might occur with all blocks that have the same id, but different damage value.
* Bows do not shoot at correct charges.
* Food takes an unnaturally long time to eat in SMP.