The outlaws' pet bear cub is a Malayan Sun Bear, of which there could have been none in medieval Italy.
When Piccolo is fighting the guardsman in the balcony he flips his sword around and holds the blade with his hand (showing it cannot be sharp) and then whacks the guardsman with the broad side of the blade near the hilt, bending it at least 20-25 degrees.
In the final battle scene in the castle, right after Count Ulrich "The Hawk" leaves the scene, the blade of a soldier spear on the floor is jiggling multiple times in the air, as it is obviously made from rubber.
When Dardo and Piccolo trip the soldiers in the castle with the pole, the lead soldier starts to fall without ever having touched the pole.