Scratch

The wiki wrote:

An RPG in Scratch is a Role-Playing Game played on the Scratch Website. They are played in three places: projects, galleries and the Text-Based Games Forum. What is often refered to as RPG games in Scratch generally have no rules or structure that real RPGs have and can be better defined as Storytelling Games.
Role-playing games are activities where people control characters and interact with others in a virtual world. Posts contain 'snippets' of a story, usually made up as it goes:
RPGer1: I go outside and check the area for intruders.
RPGer2: I make a few bottles of hot chocolate. "RPGer1, want some hot chocolate?"
RPGer1: "Yes please," I reply, taking one of the bottles and sitting down. I scan the horizon for people as I take a sip of the drink.

There would be several ways,
If you aren't after a scrolling one then you could have it so that when you reach a certain point on a background (say the bottom right corner) then the background changes to make it appear as you are in a new room.

When an event happens or you progress further down the story line you can broadcast a message to say whats just happened.
Say if you die you can broadcast a message called "death" to tell the entire game you have died so everything can act accordingly 

Basically i'd start with a single event, perhaps talking to someone, and build from there 

Hope that helps!
Neo