Unity is a multiplatform game development tool, specifically aimed at high-end game design. It is feature-rich and packed full of tools like extensible graphics, highly optimized scripting, particle effects and the Ageia physX Engine.
Because Unity is for high-end game design, some experience would be an advantage, however if you are patient and willing to give it a go with some trial and error, then you'll be surprised at what you can achieve with this very powerful 3D gaming development tool.
We don't have any change log information yet for version 5.3.8 of Unity Web Player. Sometimes publishers take a little while to make this information available, so please check back in a few days to see if it has been updated.