looks like a good map.
missing some details, such as vegetation, rocks or other.
:)

Features are best placed not via maps but via lists. Afaik SpringBoard is quite good at that.

Vegetation (=grass) isn't that awesome and will require recompiling.

In the games played so far we've had legit amphib and gunship flanks round the back of the fjord, bots can path up most of it as well.

And no, unfortunately tunnels aren't that possible, heightmaps are limited to 2d and object collision isn't able to do tunnels as far as I know