N2O (or N2O: Nitrous Oxide) is a tunnel shooter (similar to the 1980 hit Tempest) notably featuring a soundtrack composed by American electronic music duo, The Crystal Method. The soundtrack was heavily used to promote the game, and the audio tracks from the game are in Red Book audio format so that the game CD can be played on a non-console Compact Disc player. N2O was given an official port on Steam on June 29, 2015, based on the free and open-source software emulator PCSXR.