An extensive update of
Gotterdammerung 1944-1945 will be released soon
Some info on the supplemental
Festung Deutschland variant
In this variant of Gtd 44-45 the PO and deployment have been altered to model some "what-if?" situations:
In the West we may see "Unternehmen Herbstnebel" (Operation Autumn Mist), an offensive planned by Field Marshal Walter Model and his Army Group B operational staff in late 1944. It envisages a limited attack targeting the Allied forces.
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In the East there's Guderian's "Operation Schlittenfahrt" (Sleigh Ride), a sane pull-back from the main defenses along the Vistula, out of range of the opening Russian barrage (an operation historically nixed by Hitler)

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During the Battle Of The Bulge. Patton plans to have the Third Army's right flank corps, the XII, attack further eastward.
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During the Vistula-Oder operation Zhukov wants to advance directly on Berlin, as the German defences had largely collapsed.
Historically the exposed northern flank of the 1st Belorussian Front, along with a German counter-attack (Operation Sonnenwende) against its spearheads, convinced the Soviet command that it was essential to clear German forces from Pomerania before the Berlin offensive could proceed.