Another option is to use crop fullscreen mode. Then your canvas is the maximum size possible, you have entire browser window to play with. You can make a massive background (e.g. from a single pixel tile), then put your game anywhere on it by moving your objects, incl. level backgrounds around. You can put sprites and text objects into two different families, then use bullet behavior on them to move them, or pin all your objects to a background and move that. you can also set the layer scale to make the game bigger or smaller without having to do anything (this is basically letterbox scaled mode but with the ability to set your own background colour)