|Corrupt Bunnies Breaking In|
The one thing that is new before then is the ability for your weapons and accessories to have enchantments (prefixes) that are randomly determined when the object is crafted (or generated to be found). This adds a whole new element to the game as you can have a character built the same way as before but with additional things on the same items.
Such as an Obsidian Skull with the Arcane prefix will grant an additional 20 mana.
Once you do reach the end game content the whole world gets harder and you have whole new reasons to go mining, hunting, exploring and probably even rebuilding after you relize you old house isn't so safe after all.
So far I have put in another approx. 48+ hours of playing (8 days at least 6+ hours a day). This patch alone bring me up to likely over 200 hours I have put into playing Terraria so whatever you do don't buy this game, hour hands will hurt and you'll forget to do the dishes.
(actualy the is likely a very low estimate I might be putting in 12+ hours a day but don't want to admit it, but that'd be like over another 100 hours of playability since this patch. I started from the beginning again of course)