EDIT: Unity 4.2 is now available for download, and you can read a more comprehensive feature list on the official blog.

A quick google didn’t find anyone who had written this up beyond the headlines, so here’s the gritty details on what’s in 4.2, mainly taken from the Unite Nordic 2013 Keynote, here: https://www.youtube.com/watch?feature=player_detailpage&v=QY-e2vdPdqE#t=1246s

All of these are in all versions of 4.2, including the free version:

Edit: Seems I misinterpreted part of Lucas’s speech. All these features are free, they will appear in whatever version of unity is most suitable. Eg shadows are part of Unity3D Pro, so those improvements are available to all Pro users for free. Here’s the list:

Windows 8 Store export, to RT as well, so they work on RT tablets

Mechanim avatar creation API: no longer need skeleton at time of build, can be applied to new skeleton at run time. Helps with player-created avatars.

Anti-aliased render textures: useful for occulus rift because VR headsets use a render target per eye, so now they can be antialiased.

Stencil buffer access

Shadow batching: reduce draw calls of shadow-heavy scenes. ~50% reduction in shadow rendering in unity-internal shadow-heavy scenes.

Improved shadows on OSX!

Headless linux player: make linux servers from your game code. That’s pretty cool.

Fixed problems where lots of frequent garbage collection could interrupt audio.

Rigid bodies can capture shuriken particle collisions, so you can do cool things like receive forces from particles

You can cancel builds! And asset imports! And switching platforms!

Presets for colours, curves and gradients in the editor. Handy for reusing data across components.

Memory snapshot view now tells you the reasons an asset is loaded. The example shown is a texture loaded because of a material because of a bunch of meshes.

An import option to reduce white pixels in alpha’d fringes of transparent textures

And then there’s the headlines about the mobile add-ons becoming free, which everyone has heard by now:

http://blogs.unity3d.com/2013/05/21/putting-the-power-of-unity-in-the-hands-of-every-mobile-developer/

Of those new features, I’m excited by the headless player support. That’s going to be great for client-server games that want to run on AWS or something. The presets also sound interesting – I’m a huge fan of animation curves, and anything that increases their functionality is great by me. And I could have used the more detailed memory snapshot tool while optimising Sonic Dash.

So looking forward to the release of 4.2, and I hope you are too.