Gameplay wise its actually better. They didnt change much but the tweaks they did make, made it much better. Being able to use plasmids simultaneously with weapons was a nice touch and also being able to mix plasmids to create new effects such as setting a tornado trap on fire to add extra damage.
I loved the story as well and the various endings were superb and some of them quite heartwarming, yet sad. I'd still love to see another Bioshock game set in Rapture. Its an excellent world and I'd love a third game to chronicle the final demise of the city and include much more underwater segments, perhaps even with combat.
If you havent played the story DLC from Bioshock 2 I'd recommend that too. Its a decent size for a DLC, if you take it slow and search out everything it has to offer (i always do when playing Bioshock anyway) it last a good few hours and in true Bioshock style theres a sad twist at the end as well.
