This thread will summarize some of the changes added in this version of Cataclysm, it is by no means exhaustive, but contains what I deem to be important changes.
Wooden Spears can be used to roast meat and veggy chunks.
Fence posts, can be placed from the construction menu and (e)xamined to make an assortment of fences.
Evac Shelters have a bit more life to them.
Windows in houses have curtains which can be opened and closed, and may themselves be opened and closed.
Garages which contain assorted mechanical tools and have a small chance of containing an intact vehicle.
Planks may be placed over pits and spiked pits in order to make them safe to cross.
Rubble, Wreckage and ash may be cleared up with a shovel.
Metal bars (such as those found in police stations) can be cut away by (a)ctivating a hacksaw.
Cots and Rollmats, which may be placed by (a)ctivating them, and make it easier to sleep on a tile.
Some furniture may be shoved around on floors.
Select Fire mode, weapon mods and guns can be loaded at the same time, meaning you can have a grenade in your M203 without needing to empty your magazine first. (To access this feature, press the ? key, press 2, scroll down the list and assign a letter to select fire)
Small quantities of nails drop when furniture is smashed up.
Ammunition may be deconstructed and crafted, via finding a kinetic bullet puller and die set in gun stores.
Containers can hold multiple charges of liquid, such as jerrycans which hold 40 charges of water.
Jackhammers can be used to drill up roads and floors.
Walls and floors, when destroyed, have a chance of destroying any adjacent wall and floor tiles.
Fitted versions of clothing, which have lower encumbrance than regular clothes.