Systems do not have to update one entity at a time. If you need to process through several at a time, you just extend the base EntitySystem class so that the process calls gives you all registered entities for that system and not just one at a time. Name it something like CascadingEntityProcessingSystem or somesuch.

I like that idea. yes, I need to generate other System types. Currently, when you define a system, you can pass in an interval for it to be called, but maybe it'd be better to abstract that out as well.

BTW Netgnome, I saw your Journal posts on Entity System, and that got me thinking about this form of ECS.

Thanks!