The Love Update
+ Only one world can be created.
+ Survival mode has changed to existence.
+ Cheats option was renamed to superpowers.
+ Potions were given happier names.
+ There are no enemies
+ Skeletons shoot love arrows
+ Zombie Pigman and Wither Skeleton Have love swords
+ Nether portal effect was changed to hearts.
+ Clouds are changed to hearts
+ Lava was renamed to Cheese
+ Magma cubes are changed to cheese cubes.
+ Ghast now give players tours of the nether
+ Blazes now give off love particles
+ Villagers drop there items when given too much love.
+ You gain hearts by petting mobs.
- Hunger bar was removed
- Nothing ever dies

Disclaimer: this video is not mine it is the yogscast becasue they explain the update very good.