All CC0 public domain asset sources

cannon sound
Thimras
https://opengameart.org/content/cannon-fire

beam texture
Cethiel
https://opengameart.org/content/light-magic-effect

pipe sound
1up 5 - Sound effects Pack 2.ogg by phoenix1291
https://opengameart.org/content/sound-effects-pack-2

beam sound
https://opengameart.org/content/sci-fi-ambience-sfx
SFX SCI FI Hum.mp3 