Empires III as "one of the most beautiful games you will put on your computer for the foreseeable future." GameSpy agreed, stating, "Age IIIs graphics are unmatched in the strategy genre." Age of Empires III builds on and introduces new features to the prior release, Age of Mythology, such as the inclusion of the award-winning Havok physics simulation middleware game engine for the Windows version and PhysX for the Mac OS X. The innovative result is that pre-created animations are avoided; instead events are calculated according to the physics engine. Consequently, views of events like building destruction and tree felling are not pre-recorded. GameSpot also admired the graphics in the fourth release but complained about "the awkward unit behavior." Other graphical features of the game include bloom lighting and support for pixel shader 3.0. GameSpy awarded Age of Empires III the "Best Graphics" award at GameSpy's "Game of the Year 2005." Music Stephen Rippy has been the series' music director since the first game. He has had occasional help from his brother, David Rippy, as well as Kevin McMullan. He created the original music in Age of Empires with sounds of instruments from the periods in the game. These sounds came from actual instruments, and their digital samples. The tunes were the result of extensive research on the cultures, styles, and instruments used. Rippy said that sound development on The Age of Kings was easy, since there was knowledge of the instruments used in the Middle Ages. Therefore, they were able to reproduce the tunes for the soundtrack of the game. In Age of Mythology, an orchestral instrumentation was used, instead. According to McMullan, the team also collected large numbers of audio recordings from zoos, and created "a massive sound library of [their] own material." The music of Age of Empires III was similar to The Age of Kings, in which the team used more historical instruments; Rippy noted the team used instruments such as "bagpipes and field drums" to give it a realistic feel. Collaboration Ensemble Studios worked together with Big Huge Games to develop The Asian Dynasties, Age of Empires IIIs second expansion. This was the first joint venture for both teams. The reason for them doing so was compatible schedules: Ensemble Studios was busy with other projects—particularly Halo Wars—while Big Huge Games' real-time strategy team had few projects at that time. Big Huge Games did most of