Complex sentence: Wal-Mart Stores, Inc., branded as Walmart, has been subject to criticism by numerous groups and individuals such as labor unions, community groups, grassroots organizations, religious organizations, environmental groups and Walmart customers.
Split into simpler sentences: Wal-Mart Stores, Inc., branded as Walmart, has been subject to criticism by numerous groups and individuals. Among these are labor unions, community groups, grassroots organizations, religious organizations, environmental groups and Walmart customers.