The results are in!
A: Attempt to reinforce the walls with metal (0)
B: Withdraw troops, and attempt to surrender (2)
C: Attempt to steal an enemy gun, to find out how it works (3)
D: Set the wall aflame (2)
Yay for technology!
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The leader decides that his own technology is no match for these new aggressors, and so the only viable option is to steal theirs; the order was simple, periodically a small group of soldiers should be sent out to retrieve a weapon from a dead enemy; the excellence of these enemies was overlooked however, and it took many days for the weapon retrieved.
And what a wonder it was! Like some of the more advanced muskets, used by mounted soldiers, the powder and projective were loaded in a single casing, but unlike the muskets, several rounds were stored in the gun, each being able to load itself, with no more interaction from the user than pulling the trigger; it would take weeks for his scientists to fully disassemble it and figure out the workings.
Weeks he did not have.
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What should The Leader do?
A: Put more scientists on the team, attempt to rush the process
B: Use fire-arrows, a primitive weapon, nontheless proved effective in battles past
C: Institute a draft, to help uphold defense
D: Issue builders to the area, to patch up and maintain the wall