Official referees
After I wrote those referees, the real ones used by CodinGame were leaked here. Those are the single source of truth if you want to understand how the game really works.
CodinGame Referee Collection
This is an unofficial collection of referee programs for CodinGame multiplayer games, compatible to brutaltester. The referees are not ported from the code used on the servers, so correctness can't be garanteed. This applied especially for, but is not limited to map generation.
The referees support some basic graphic feedback.
To activate it, pass a folder (or . for the current directory) as first command line argument and you will get an image for each turn.
This is not recommended when playing multiple matches, as it is slow and images will be replaced by later runs.
Getting started
The referees are written in C#. On Windows the sould run out of the box (Windows XP with service pack 3 or above). If not, check for updates of the .NET framework.
On Linux install the mono package with apt-get install mono (Ubuntu) to execute the referees.
Not implemented
HyperSonic
MOVE doesn't find shortest paths. It works fine, as long as you always go to adjacent cells. When you use the referee to optimize you bot, you most likely use your own pathfinding anyway.