It looks just like Helm's Deep! Nice one, Kevin!
Its also perfect for a survival mode, since Helm's Deep was kind of a corner that Rohan backed themselves into in LoTR. There was no way out, and they all knew that they were probably going to lose. That, or you should have to survive for a certain amount of time until help arrives (like, 20 Elven Archers show up out of nowhere when things are at their worst and save you from an untimely demise).