Kingdom Company was an interactive play based on Shakespeare’s Richard III. Using the Source engine and Synergy Mod for Half-Life 2, we built an interactive world, where (on the nights of the performance) we assumed control of different characters in the story. The player could converse with us via voice-chat, allowing us to adjust the dialogue and story events on the fly. From a hidden room in the game, we could trigger special events and teleport around the world. The player sat alone in a room, while the audience could both view the world from her eyes and see us operate behind the scenes.
On this project, I focused on level design, narrative/game design, and gameplay scripting within the engine. Some folks at Valve were kind enough to give some tips and tricks.