I didn't find anywhere to declare this, but the sfx, font and gfx assets of the game are pre-made and acquired from free sources, e.g. itch, opengameart, dafont, freesound.org, etc.
Special credit to the following itch creators:
https://cyberrumor.itch.io/ - characters
https://szadiart.itch.io/ - tileset