Tiles, items & creatures: Pixel Platformer by Kenney (CC0)
Music & sound effects: 5 Chiptunes and 512 Sound Effects by Juhani Junkala (CC0)
Jingles: Music Jingles by Kenney (CC0)
Font: Press Start 2P by CodeMan38 (OFL)
Axolotl, heron, shrimp & tilapia sprites drawn for this game.