I think specific units (like fuel launcher and flare gun) should have an specific firing lane, because I guess that aiming with bazooka-like weapons is difficult and more limited. For other weapons like the nailgun for example, there shouldn't be a firing lane, he should be able to fire to 360° of his position, or at least, 180°, a semi-circle. That would make more sense.
I really understood the gold bags things (I do read the instructions), the thing is that they'll keep bouncing in any direction except to the exit, take all the gold and get bored. Better AIs for the adventurers.
For easy cash just set the looter and burglar in the team, and complete over and over the beach front. Find a place with 1 bug and hit that same square all the time, you'll get about 2000-2400 bucks a day.