To move your knight horizontally, tilt your device from left to right. The Knight will then move corresponding to the side you tilted your device to.
To attack enemies that are below your Knight, tap on the screen. Your Knight will then attack any enemies directly below it, and then bounce back up into position.
On the left side of the play screen, you will notice a bar that you will fill up as you kill enemies. This is known as the Boost Bar and will make the game move a little bit faster each time you fill it. This will make the game a bit more difficult as a result, but you’ll also progress faster if you can deal with the quickness.
Completing missions will give you keys and gold you can use in the game.
A good upgrade to take on in the early goings is the Boots that will allow your Knight to attack much faster than before, meaning you will land more strikes on enemies when you’re still learning the basics of the game.
As you're making your ascent up the tower, try and get your knight to stick to the edges a lot. Attack those enemies when you get the chance but when the screen isn't as busy as before, push your knight to the edges of the tower.