Complex sentence: In the US, it sold 570,000 units in its first month of release, making it the fourth best-selling game of March 2013, which is significantly less than "God of War III's" first month sales, which were 1.1 million units.
Split into simpler sentences: In the US, it sold 570,000 units in the first month of its release, making it the fourth-best-selling game of March 2013. The game's sales were significantly lower than "God of War III's" first month sales, which were 1.1 million units.