I was working on something similar for a game. It was a 2D adventure type game. The idea was to have a single image as the background with walkable areas (stored in an array) along with hot spots to make things happen - some hot spots were exits while others could do things.

I got as far as making the character walk around the screen avoiding blocked areas and reaching exits. I never got any further

I even had the various adventures designed for the game. I had a world with about 15 screens (backgrounds were ready) and then lost interest. It would have been for the remakes.org one button contest.