The art style. The same plasmid-style upgrade system. The general theme of a corrupted society. The genre (FPS). (Is that enough, Wrath of War, or do you have more of your own ignorant comments to add to the discussion?) How is the setting similar? Bioshock was under-freaking-water in an art-deco biome. Dishonored is in a Victorian-esque cityscape. You want more intellectual smack downs or are you good?