> the first step in our research towards more complex interactive worlds

As we know, object permanence is not really needed in any videogame, so this makes sense. It's also easy to add in, they just didn't do it because they didn't feel like it.

Snark aside, not sure what that is supposed to mean. This isn't interactive in the same sense that games are, its not a world because it doesn't have any properties of a world, its just a video generator you can steer with keys. Cool, but not what we would call an interactive world