This guy, who would probably be considered a mini-boss, was a good choice to implement because it exercises a number of game systems we haven't seen yet. In particular:
The weak points are a new feature, but child objects and enemy weapon fire were already in the engine. And it turns out there were some major problems with all of those, so it was good to get that sorted. As far as being a powerful enemy itself, I was thinking of adding homing missile fire to the Ratte -- another new feature, not implemented yet -- but if you don't have wildly overpowered weapons it's a pretty tough customer even with just the one turret. So I may hold off on that for the moment and get on with other things.