If you don't like narratives, that is. Episode 2 is run-of-the-mill Half Life (get to the lab across a great distance, quick!) with some plot twists thrown in. Combat's about the same, if you substitute Big Daddies with Hunters and splicers with Combine Soldiers, antlions and zombies. Ep 2 has a strider battle, Bioshock has soup-thick atmosphere. Plus, Bioshock's longer and isn't just part of a larger picture.