This is a comprehensive walkthrough of the game Horn, and will be riddled with spoilers. This could be useful if you're stuck on a part of the game, want to find all the blueprints, journal entries, and other hidden secrets. All this is in Story Mode, not Quest Mode.
Introduction: The Foggy Vale
The game starts off with a lovely cutscene, a nice voice actor, and good cardboard cut-out graphics. After the introduction cutscene, you begin your journey on the floor of a huge ruined column in a place called the Foggy Vale. You then automatically receive your first journal entry: Awakening. Take one step by tapping on the ground, and you will find a horn and a crystal shard on the ground. Continue forward to the door, where you will grab a rusty sword, thus gaining your first weapon and opening the door. Press on, through the opening, and collect- what's this? It looks like a blue rupee! Well, that's essentially what it is. It's called Pygite, and it's one of two forms of currency in this game. Walk up to the reeds and slash them away by swiping back and forth on the screen. That should do it. Go out into the open and drop down to... another cutscene! You have seen your first Pygon. Make a right turn and jump over the gap by tapping the other side. As Horn tries to be polite again, the Pygon continues to jump away. Pursue him by jumping the other two gaps. The Pygon is now beginning to shoot lasers at a poor flying pygon, which turns into a... bird? Continue to track the Pygon by pulling yourself up a ledge. After a brief walk, you will find yourself face to face with this cowardly Pygon. The fighting demo begins here, and you learn to fight with your weapon, by swiping the screen, rolling left and right, and using Potions and Pybooms. Once you knock off its head, you can continue straight to the opening.
Once you emerge from the passageway into Area 2, you need to cross a narrow path on the right. When you get to the other side, you can zipline all the way down. Whee! As this confused Pygon tries to find his head, you can continue going left and jump across a river, using his body as a stepping stone. Then, you stumble across a gauntlet on the other side, which shoots blue laser beams. You are then "challenged" to shoot three flying pygons. Turn left and pass under some debris. This brings Horn to a crossroads, Cuthbert and Suddene, both are areas that Horn will get to eventually. All that lies to the left is one pygite, but there is a pygon on the right that you will now engage in combat. As soon as it is killed, another huge pygon comes in its place. This pygon can do some decent damage to you, but when it's halfway killed, it comes in for a finishing blow, effectively exposing Horn's crystal he found at the beginning, finishing off the pygon, who transforms into a sweet old lady, Aunt Bell.