Just adding my grain of something so you know.
I've created our own graphics adventure engine at my job, running on Flash and using XML files generated by a tool created by our Game Designer. It pretty much solves all needs when creating a Graphic Adventure and supports most classic features with a nice interface for developing the adventure itself. It could even run on other platforms if the XMLs are interpreted correctly.

Here are some games we created with it, the engine itself got upgraded from one game to the other as seen in the improved game quality:

Rodrigo Vieytes

PS: love your game, don't ever leave this world please.