My old copy of this classic Jim Dunnigan designs came out to play today as I am minded of the Dunkirk commemorations this past weekend. This is still fun to play and the design works in that it clearly illustrates the impossible position the allies put themselves in which made the German invasion of the Low Countries and France an easy thing. Playing the historical scenario, you can see the German build up and push through the empty Ardennes (save for 1 Belgian cavalry unit) and the breakout. Then the race is on to save the remnants of the Allied armies before the panzers sweep them up in the blitzkrieg.
Classic by Avalon Hill and designed by Jim Dunnigan, one of the Fathers of modern wargaming.