Licensed under the terms of the MIT license found in LICENSE.MIT except for:

matrix.lua: see matrix.LICENSE

hump: see hump/README.md

resources/audio/Beavis II.mp3 made by Maf is licensed under CC-BY 3.0
https://www.youtube.com/watch?v=MVl_FoPD34s

resources/audio/chaingun.mp3 and resources/audio/vickers77.mp3 are licensed under CC0
https://www.facebook.com/freefirearmsfx

resources/audio/clangs/* made by bart are licensed under CC0
http://opengameart.org/content/33-metal-clang-sounds-cast-iron-pans

resources/graphics/sky.png made by bart is licenced under CC-BY 3.0
http://opengameart.org/content/sky-backdrop