I found it easier to survive in the large room to the west. Gives you more kiting room for the spells they shoot at you. Save up for machine gun, once you have it set up 2 or 3 turrets in the room with you. Was never in danger of dying.
Things happen in a pattern. If there is one guy on the ground shooting at you, chances are there are two behind him. If there is a mine in front of a grey building there is a very good chance there is a guy on that building. Once you get a few runs under your belt you will see these things and they just keep repeating.
The way you repair the walls and the archers HP is to mouse over the icons underneath them, not click. You can leave your mouse on one of them while you are fighting to repair during the battle.
Odd game. The last guy didn't even do any damage to me. I just stood there swording his face in.
