Prog Rock or Progressive Rock to give it it's full name, is looked down upon in this day and age. To many it is seen as pretentious and ridiculous, and to be honest it did get that way.... with 20 minute keytar solos and unlistenable tracks which only made sense when you were stoned (apparently, as I've never touched drugs to check the validity of this statement). However this is a disservice to the entire genre, there were amazing bands who pushed the boundaries in live shows and wonderful albums made, and their influence can still be felt today in bands like Arcade Fire, Muse and Radiohead.
But for a whole generation of computer game composers Prog was the inspiration for their music, especially in Japan, Germany and Italy where Prog seemed to really resonate with the people. Legendary Final Fantasy composer Nobuo Uematsu cites Emerson, Lake and Palmer and Uriah Heap as his inspirations. Tim Follin, game composer for many NES, C64 and SNES games has said that the audio limitations of older machines created a challenge when working on computer game music; to create music that was not only enjoyable the first time but also on subsequent loops until the level/ boss/ mission was done.
Prog Rock offered a good link as many albums were concept albums which contained characters, themes and stories... not too different from computer games. A lot of 8 and 16-bit games could get very intricate and complex and the music had to reflect this and so you had a situation where games composers were liberally borrowing elements from Prog Rock.
One of the best examples I can think of is the last battle in Final Fantasy 6, where the team face off against Kefka... listen to this piece and tell me it's not Prog Rock inspired. The game left such an indelible mark on me that I even created a deadpixels cover homage of it with me and Simon as lead characters. As well as being an epic battle the music is such an integral part of it, composed in 3 parts to reflect the 3 transformations of Kefka.
Rick Wakeman , the legendary keyboardist from Prog Rock group 'Yes' went solo in the 70's to create thematic albums around books and history. His most famous work is 'Journey To The Centre Of The Earth' which was a landmark achievement, selling over 15 million records worldwide. 2014 marked the 40th Anniversary of the release of the album and I was lucky enough to get tickets for the concert at the royal Albert Hall.
The concert was amazing, a real spectacle. To see a sellout audience silent and entranced by Rick Wakeman and his orchestra brought home to me the fact that even though Prog did get crazy mad, there were still amazing gems that still shine today and this was one of them.
Prog is not dead, it is alive and well!