This is really good, I love the energy of it, but I did find the transition at about 39 seconds to be a bit jarring. Since you're opting for an incidental style, what is the foreground that this music accompanies? For me, the first part of the piece was almost combative, and so maybe a good way to extend this idea is to represent a sense of impending peril beforehand and some kind of aftermath afterwards? In this example from Lord of the Rings you really the build up, fight (starting at about 3 mins in), the aftermath (5:20 onwards), and then the flight (at 7:20.)
So, maybe map out a scene with individual 'beats' (or 'moments') and then write around the really good section you've already put together?