The gradient background in the above screenshot has been drawn to a secondary canvas, which is then redrawn onto the main canvas.
This seems to work reasonably well, and should hopefully allow for a fair number of generated backgrounds and other such effects, without requiring huge 1024x1024 background images to be downloaded.

The whole thing runs a little slowly on my Samsung Galaxy 10 A, however, so I'm going to have to add an option to disable the buffer when necessary.
But otherwise.. Yeah.. Works alright!

If you'd like to try out the engine for yourself, head on over to the imaginatively titled Browsercade.com and you can have a short play about.

Most-everything should work with keyboard.
You should also be able to plug in a gamepad, and have it work.
Tapping the tiny button on the bottom left of the main menu will open up the touchscreen buttons, and you can test those out, too, should you be on mobile/tablet.

Do be aware, the collision detection in the "game" isn't 100% yet!

But otherwise, you should be able to get a good enough feel for the controls.
Be sure to let me know if it's up to regular AGameAWeek standards!