Thanks guys, these are helpful. I'll start with Unity, and try Anarchy next. I have a feeling Unity will suffice though, assuming Unity can handle high polycounts.
Unity doesn't have post-processing (which includes motion blur) in the free version, though. So you'll have to sacrifice that. I don't think your scene (looks to be rather lowpoly) will give any performance issues.
@Snader I feel like the polycount will be an issue as the map develops larger. This one is already 140k with 10 different 2048x maps and even this is a relatively small map with many repetitions. Considering the movement speed with be fast, theres not much to fly through here. Are you sure Unity can handle this ?