The Goal

Don't get destroyed by the troll.

Rules

You have to shoot at least 1 stone per turn if you have any left.

The following points are still ideas in flux, waiting for some opinions (leave a comment on the draft submission page!)

Is it even worth publishing? can the problem be totally solved?
More maps? (a map is a {road length} × {initial stone count} pair)
Leagues? I could conceive the referee being permissive (allow 0 stones thrown) in the first one, and then strict.
Fog of war? (see only troll position, not enemy throw/stones left)
variable for of war? (seeing enemy stones is a boolean decided randomly as part of the map?
alternative fog of war? (seeing enemy stones only when troll is close to us?)
Praise for my artistic skillz
Other remarks?

Victory Condition

Your opponent loses.

Defeat Condition

Just read the sample code. You can figure this out.

Enforce the one-stone rule. (that also fixed the legacy buh—sorry people! I put an easter egg in exchange)
Cutesy defeat animations.
Distinct castle sprites!
Terminate game when there are no more stones in sight.
More pretty. (SRLSLY)
No more void maps. (root cause: Java % on a negative seed)

Based on an involuntary suggestion by Zaap38 on the #Fr channel. The original appears to be by Romain André-Lovichi .