Microsoft's highly-anticipated Zune HD made its retail debut today, as expected, and along with the launch came a few more details about the software behind it. Although for some reason the company decided to ship its player in a largely non-functional state, once you download and sync the new 4.0 firmware you'll get a hold of the new features, which include Smart DJ (Microsoft's version of iTunes Genius) and a new Quickplay menu to access your favorite media.

The user interface has been revamped to support multi-touch gestures, though overall the organization and layout is mostly the same. Some noticeable changes include an updated store stocked with new HD movies, rentals, and TV shows as well as an optimized Zune HD browser that fully takes advantage of multi touch.

Interestingly, Microsoft also revealed plans to position its Zune HD device as a mobile gaming platform. Later this year, in addition to releasing free applications such as Twitter and Facebook for Zune, the company plans to offer 3D games such as Project Gotham Racing: Ferrari Edition, Vans Sk8: Pool Service, and Audiosurf Tilt. For a closer look at what the new Zune HD has to offer, check out this report at Electronista.