just bought this wonderful game and have played 8 fights so far...
i'm asking for clarification about couple of rules here:
1. does level 2 hill bring you +2 FP & DM compared to level 0?
No - just +1.
2. if i'm hiding behind the wall and opponent advances to a hex where he could potentially see behind the wall, does my hidden unit reveal? (in this example russians are "hiding", and germans advancing to the stone building)
can they see me from the stone building?
If you draw a line from one unit to the other (center of the hexes) and it doesn't cross the wall, then the wall will do no good in helping to hide. So in the example you give, where the units are shown in the picture, the wall would help in hiding the unit, but if the unit were in the stone building, then no, the wall would not help.