Just finished Bioshock 2 and really enjoyed my play through the game. My concerns about not being powerful enough were completely swept away as I progressed with more powerful plasmids and gene tonics. I opted for the "Drill Specialist" approach for the latter half of the game. This somewhat misleadingly named gene tonic doesn't actually make the drill more powerful at all but it does greatly reduce the EVE requirements of plasmids at the expense of disabling all weapons other than the drill. By combining powerful plasmids with an upgraded drill I was smashing through everything in the game by the end. All the plasmid powers can be useful and it is easy to see that you could select a wide variety of play styles. I used Swarm of Bees extensively with frosty blast to freeze harder enemies while I drilled them to bits.
The story lacks the literary pretensions of the first Bioshock but still hangs together well. There are some lovely touches including a sublime segment where you get to play as a little sister.
The game still features re-incarnation at vita stations which I don't like and never used. If you die during a fight you are re-incarnated at the nearest station while the mob has not recovered from the fight. I guess you can clear any enemy by repeatedly dying taking a small chunk of health on every death but I much prefer to quick save before a fight and keep trying till I get it in one go. Unfortunately Bioshock 2 has quick save and quick load buttons right beside each other which caused a couple of annoying mishaps. Nevertheless a thoroughly enjoyable game. Recommended.