Unity 3 is a game development tool that has been designed to let you focus on creating amazing games.
Simple
With Unity 3, weve put tremendous effort on world building tools – so you can assemble and tweak your levels at the speed of thought.

Powerful
We rewrote Unitys rendering pipeline so your games can look the best they can – and get a 50% performance boost on top.

Unity is the tool for the job
Unity is the development environment that gets out of your way, allowing you to focus on simply creating your game. Developing for web, mobile, or console Unity is the tool for the job.

Whats new in 3.4.0
Allegorithmic Substance Integration
Assign and adjust procedural textures right in the editor or at runtime
Stream huge levels with textures only taking up a few Kb
Bake to normal textures and materials for mobile devices
Editor Improvements for more efficient game development
User-assignable Scene View icons
Modifiable primitive colliders
Per-component gizmo collapsing

Note
The included crack, will make this a fully licensed working copy of Unity 3.4.0f5. It will allow you to compile games for the following platforms:

Mac OS X 10.x.x
Windows XP7
iOS 4.x (iPod, iPhone & iPad)
Android

However the crack DOES NOT COVER the following:

Xbox 360
Playstation III
Wii

Link for more information: http://unity3d.com/unity/