This film is created out of composite characters, most notably Henry Fonda, as a Lt. Colonel in Intelligence and Robert Shaw, as a Panzer Brigade Commander supposedly just recalled from the Russian Front, where he was "losing the war there".
According to the official account, the part Robert Shaw fictitiously portrayed wasn't the Colonel Hessler he was titled as, but; Joachim Peiper, and the following is from the official account; "The 6th Panzer Army included the elite of the Waffen-SS, including four Panzer divisions and five infantry divisions in three corps. SS-Obersturmbannführer Joachim Peiper led Kampfgruppe Peiper, consisting of 4,800 men and 600 vehicles, which was charged with leading the main effort. However, its newest and most powerful tank, the Tiger II heavy tank, consumed 3.8 litres (1 gal) of fuel to go 800 m (.5 mi), and the Germans had less than half the fuel they needed to reach Antwerp."
The film was built around the German strategic objective being beyond their reach in fuel and other vital strategic materials. Why did they use fictitious characters where the real ones would have done even better? Less than 20 years after the war and the events makes the responsibility of depicting real historic and often heroic or infamous personalities a tall order for the mainstream cinema. One must remember that this was a commercial production, not an historic account.
The famous and catchy song, sung in the movie as a theme of the Panzer Corp., in German, "Panzerlied", was written for the movie. It can be found on "You Tube" and is apparently both catchy and popular--- it also didn't happen that way.
Still, to be fair, when we first got a Video player, around 1981, the first movie I watched was "The Battle of The Bulge", despite all its historical inaccuracies, because its entertaining and I'm sorry it has to end. In reality, it was more unpleasant than depicted and the Hollywood movie starring Van Johnson from around 1948, titled, "Battleground" presents a better reenactment, though also fictionalized and from the standpoint of 1 small allied unit rather than the broader scope depicted in "The Battle of the Bulge".
This is an excellent, high budget film with good actors, and acting that shows both sides, and attempts to demonstrate what the "Battle of the Bulge" was actually about. It does this well, from a Hollywood standpoint, though films such as "Patton" were made a few years later using the real characters, and based on reliable source materials with somewhat less fictionalization.