N2O (or N2O: Nitrous Oxide) is a tunnel shooter (similar to the 1980 hit Tempest) notably featuring a soundtrack composed by the American electronic music duo, The Crystal Method. The soundtrack was heavily used to promote the game, and the music is stored in Red Book format meaning the game disc can be played as a music CD on an ordinary CD player. N2O was given an official port on Steam on June 29, 2015, based on the free and open-source emulator PCSXR.