Honestly i thought Bioshock was shallow, i regretted buying it immensely. They focused too much on constant combat and goal-based gameplay and less on immersing you in the story.
Having said that, Bioshock has it's 1920's themed music and guns which draw you in all on it's own. The big thing about Bioshock which affects how replayable this is, is the almost infinite number of options between guns and plasmids. In HL2, it gets boring fast using 5 main weapons throughout a game where you fight medium to long range and all 5 can't shoot accurately past short range.
The physics lacked, big time in bioshock and contrary to others' opinions, I did not see, water/fire/heat effects aside, any graphical difference. HL2 has much better realistic faces.