sound/expl-player.wav:
  Blender Foundation (http://apricot.blender.org/),
  submitted by Lamoot (https://opengameart.org/content/big-explosion)
sound/expl-enemy.wav:
  Stephen M. Cameron
sound/mus-04b.mid:
  Akihiko Shimizo, Arranged by: Gordon Glas
sound/mus-06.mid:
  Jan van Valburg
sound/mus-07.mid:
  1996 by Actual Entertainment, Inc., Seppo Hurme
sound/mus-10.mid:
  DECO 1988 (Data East Corp), composed by: Tim Follin, sequenced 2000 by: Magnus Andersson
