This is an awesome stepping stone for "game-play" style development for screeps beyond the sandbox world. Exciting stuff.
edit: I must say, the screen-shot indicates the possibility of a "snake" style joined creep, sorta in the vision of CyberNinja's post: http://steamcommunity.com/app/464350/discussions/6/152390014794733505/
Awesome. I hope to see more NPC... things... in the future.
I do so hope we see some singing creeps pass through.
it seems weird that this post isn't in the changelogs category on the blog. made it hard for me to find.