[gcanyon]

I guess I get the clarity (of vertical slides as you describe), but I'm wondering if two dimensions is limiting -- slides could be a flow chart, with various forks/side quests along the way. Obviously it would be possible to build something as confusing as the Colossal Cave, but the vertical slides use case would easily be a subset of that larger functionality, and it would leave it up to the user to decide their level of need for/tolerance of complexity.