Unity is a multiplatform game development tool, designed from the start to ease creation. A fully integrated professional application, Unity just happens to contain the most powerful engine this side of a million dollars.
I Really love This Game Engine. Why ?? Because Unity Have Many Features And HQ For Appearance. I Only Have 4 Example Game Using This Engine :
1. DreadOut (Indonesia)
2. IFSCL (Immudelki) [Only A Bit But Great]
3. Uberstrike (Facebook)
4. SuperColtTycoon (I Dont Know The Source)
And This Engine Support Many Platforms Like Xbox,PS 3,Windows,Web,etc But I Waiting For PS 4. Heheheh Really. Thank Unity
Unity makes collaboration for little independent game studios very easy.
Furthermore it saved my freelance life, because I could iterate so quickly through different prototyping-stages. And that's important for certain projects, above all for projects which will feature complete new stuff!