This is my first forge map and Hopefully not my last. I loved Valhalla in Halo 3 and would love to see it come back as a map in Halo Reach. I know the bases in Halo 3 were not round but it was the way i could get the tunnels under the base close. The Valley Blue Base Red Base
The only thing I see in this map that is identical to the map is the bases and the vehicles on the bases. Other than that, it just looks like a blank map with a few rocks.
This is O.K. in general but I would have liked more detail. You have the designs mostly right just the middle section of the map was the main attraction.
I think a few additions to this map you make it better. Creating a thinner canyon would be good, adding a structure like the downed pelican would also help.