Armchair General reviewed WWII Barbarossa 1941’s expansion including the Danube campaign.
From the review:
ArmchairGeneral.com reviews Zvezda’s World War II Operation Barbarossa 1941 and its first expansion, Battle for the Danube. The base game comes with 21 snap-together models, plus some 3D terrain and flames and smoke. The game is easy to learn, plays well despite some rules issues, and would be ideal for introducing new people to the hobby.