Complex sentence: The game is set in European theatre of the war, and is centered around a squad in the 1st Infantry Division, following their battles in the Western Front; the multiplayer expands to different fronts not seen in the campaign.
Split into simpler sentences: The game is set in European theatre of the war. The campaign is centered around a squad in the 1st Infantry Division, and follows their battles in the Western Front, while the multiplayer expands on different fronts not seen in the campaign.