Complex sentence: Happy Home Designer is a sandbox video game developed and published by Nintendo for the Nintendo 3DS, with assistance from Monolith Soft, and released in Japan in July 2015, in North America in September 2015, and in PAL regions in October 2015.
Split into simpler sentences: Happy Home Designer is a sandbox video game developed and published by Nintendo, with assistance from Monolith Soft, for the Nintendo 3DS. The game was released in Japan in July 2015, in North America in September 2015, and in PAL regions in October 2015.