How to Solve the Darts Puzzle
The darts puzzle is bad game design: In any game, a puzzle is expected to be solvable in some kind of way. Therefore hints exists. In the case of the darts puzzle, that hint is the dropped red arrow on the floor and the note in the drawer.
Those hints imply that the red dart was at some point attached to the board and fell down. This means you have to somehow figure out the original position.
As we cannot assume that there is a hint missing (it is on the ground after all) we can use our environment to try to derive that missing info from things immediately around us: The dart board. Here comes the design flaw:
The dart board offers an intuitive hint: A very prominent black pixel on the surface at the number 6:
It is even on the right side of the board and the only visible imperfection. That has to be the hint! But adding the arrows does not give the right solution. Hm. Wasn’t there a rule sheet at the inn ? Maybe we are calculating things the wrong way. So then you work through the 501 rule-sheet which is further confusing as it opens many possibilities on how to calculate a possible score. Combined with the switiching of digitis (0 at start or end?) you now have people thinking they found the clues but cant put them together.
Then you have a 4 digit code with a 3 digit solution giving a lot of ambiguity to any possible combination. Especially if you are following a wrong clue.