There's not really any walkthroughs at the moment since this game is in active development and is subject to many changes until its actual release. Here is a map of everything that's in the game so far.
When the game is officially released, the level design and layout might be drastically different.
One hint to activate the fight for the Gnu girl (Cynthia) is you'll need to find the mushroom dog and feed it any mushroom to make it follow you. Once you do that, take the dog with you to Cynthia, located on the far top left and press the button when prompted to start the battle.