The first nine minutes of the film is one continuous choreographed tracking shot, beginning with a closeup on a candle flame, to oaths of fealty, to a duel and finishing with the firing of a trebuchet on a castle.
Following a screening of the film at the Toronto International Film Festival, director David Mackenzie decided to cut 20 minutes from the film. Among the scenes cut was a battle scene set against the backdrop of a waterfall, an eight minute chase sequence and an encounter between Robert the Bruce and William Wallace in the woods.
The Prince of Wales is depicted in this movie. He was the first to ever hold this title. His father Edward I had conquered Wales which had a policy that no-one born outside the Principality could rule. Edward therefore, transported his heavily pregnant wife to Caernarfon Castle (which he'd built to keep the Welsh in check) so that her son, Edward was born in Wales. King Edward then promptly declared his son Prince of Wales, thereby stealing the crown of Wales and sealing the Principality's subjugation to the English Crown. The heir to the UK Crown holds the title to this day.
The first cut of the film was around four hours long.
Robert's father and Edward I did in fact fight in the 9th (and last) crusade. During this time Edward was almost killed in an assassination attempt. The crusade was generally a success for the English and allied forces but conflicts at home forced Edward to leave the campaign, at which time the crusade spirit had mostly died off.