All listed assets are CC0.

Public Pixel
GGBotNet
https://ggbot.itch.io/public-pixel-font

Spooky Dungeon
Memoraphile @ You're Perfect Studio
https://opengameart.org/content/spooky-dungeon

newbattle
celestialghost
https://opengameart.org/content/8-bit-battle-theme-famitracker

void_estate
Zane Little Music
https://opengameart.org/content/haunting-chiptune-loop-void-estate

mysterious_sewer_overture
smark
https://opengameart.org/content/mysterious-sewer

Sound effects by Shiru
https://opengameart.org/content/nes-8-bit-sound-effects