Quite accurate. It appears that the events portrayed in the movie are based on the actions of the SS Dirlewanger Brigade (named after its commander Oskar Dirlewanger). After spending some time in Poland, where the actions of the unit were so brutal that the SS complained, they were sent to Belarus for anti-partisan operations. In Belarus, their usual method of operation was simply to kill civilians (rather than partisans). Burning civilians alive in buildings, machine-gunning those who tried to escape (as portrayed in he move), was one of their common methods. Beating, shooting, and raping were standard procedure for their interaction with civilians. Again, the SS complained - Dirlewanger's atrocities were extreme even for the SS. In Belarus, they probably killed from 30-40,000 civilians, and a handful of partisans.

Their next major action was in the suppression of the Warsaw Uprising. Again, beating, shooting, and raping were standard. However, the Warsaw insurgents fought back more effectively than the unarmed peasants in Belarus, and Dirlewanger's unit (officially now a regiment, but with a strength of under 1000) took approximately 3000 casualties. Again, some in the SS complained about the extreme atrocities, but others in the SS approved of his "effectiveness" - he was awarded the Knight's Cross. Near the end of the war, the unit was largely destroyed in the defence of Budapest (except for an entire battalion newly conscripted from communists imprisoned in concentration camps, who understandably took the opportunity of being on the front line to desert en masse). They were reconstituted as the (understrength) 36. Waffen-Grenadier-Division der SS, and finally destroyed in the Battle of Berlin.

In summary, the movie is accurate, for the time and place - Belarus when the Dirlewanger Brigade was operating there. The movie only shows fairly "typical" Dirlewanger atrocities, and not their more extreme ones. Dirlewanger's atrocities were extreme not only by German standards, but even by SS standards. This was not unique to the Dirlewanger Brigade; it was also a feature of the activities of other SS units formed for anti-partisan warfare (i.e., for killing civilians in areas where partisans operated).