If you use the same resolution in all devices, you can end with a game that don't use all the screen available in the device. That is because you game can have a resolution that has a different aspect ratio of the screen device. The lib calculates a new resolution based on your default resolution that have the right aspect ratio.
Native games locks the screen orientation, but mobile browsers don't (for html5 games). The lib checks for orientation changes and provide a callback where you can adapt your game. Generally sponsors asks to show a message asking the player to rotate the device to right orientation, so there is a example that shows how to do that.
Create and remove links that act as buttons that stay in top of the canvas, and respect the scaling of the game.
- HTML5 Fullscreen API