MISSION ONE - RIMTECH CAMPAIGN

 
The top-right corner of the screen (top of toolbar) contains the level's minimap which displays the basic terrain of the entire level.  The dark areas on this map represent the "Fog of War", or terrain that cannot be seen by any of the player's existing units.  Notice the yellow buttons beside the minimap.  These represent the game's three different layers: the orbit layer, the surface layer and the underground layer.  The player is currently looking at the surface layer, so that button is highlighted.  If the player left-clicks on the "All" button (or hits 'spacebar'), the toolbar will display all three layers at once.

NOTE: This mission has only the surface layer.  The second mission has the surface and underground layers, and the third mission and after have all three layers.