BioWare wants "Mass Effect 2" to be both darker and harder than its predecessor, and the studio's co-founder Greg Zeschuk wants one classic space opera to be the benchmark for its continuing story. "Star Wars" traded the sandy, sunset-glazed atmosphere of Tatooine for the barren snow of Hoth and the blackness of space in "The Empire Strikes Back." Zeschuk wants to reflect the same sea change in the second "Mass Effect."