I'd rate DFX a "fair" game (6). Of course, I'm comparing that to previous Nova projects.
As a mapper, I'm still not satisfied with the lack of AI control. Having said that though, I do get a kick out of the AI animations; they're pretty good. DFX is good for eye-candy. Nice gfx. Nova did a better job with lighting and shading on DFX than they did in JOps, where everything seems to "glow".
For mapping, once you get the hang of making wac files or bin files, it's entertaining enough to rate a 6. But it doesn't raise my adrenaline... like BHD does.
