/level/level2.ogg by cloudjumper, CC-BY-NC-SA
http://soundcloud.com/cloudjumper/

Licensing information will hopefully be added for:

/anomaly shot/graviton_anomaly.mp3
/anomaly shot/repulse_anomaly.mp3
/menu/button_clicked.mp3
/ship_destroy/fighter_destroyed.ogg
/ship_destroy/mothership_destroyed_long.ogg
/weapon_shot/pulse_cannon_single.ogg
/weapon_shot/pulse_cannon_triple.ogg
/weapon_shot/rocket_shot.ogg