The silo icon looks good (if imagined with solid lines^^). Since the area where it is located doesn't allow a bigger icon, i think it's a good choice to have the symbol on it instead of the "front-view" buildings on the other icons. For the colors it's ofc more a question of personal taste, but i think the addition of the orange will help. I'm curious how the expanded map will look like.
Btw., will you stick with the font for the title? I just thought that maybe a somewhat "old-school" calculator-like or pixelly font might look fun on this map?