Too easy? what diffculty are you playing on, im yet to survive a fight with a big daddy, usually kill him after my 3rd death and thats on hard.
After the first level i found it rather easy on Hard. Maybe it had something to do with me completing Bioshock last week and knowing what works.
It actually took me quite a while to get used to the controls and using the plasmids, and for about the first 2 levels i barely used them. I only really used 3 different plasmids and upgraded them fully and left all the others. Finished the game with loads of spare adam :/
Overall i enjoyed it, but a few things i loved so much about the first were missing:
1) The recordings in the original were twisted and amusing and i enjoyed listening to them. In 2, i had to wait till the last level for a recording that made me laugh

2) 2 lacked a decent score i thought, and one bit in particular (a hotel i think it was) had some horrible screechy music playing throughout which in the end forced me to keep pressing the recording playback button to cut the horrible noise out

3) I didn't really like and of the characters in this one, probably because of the lack of humour. In the first they stood out, they were funny, you actually looked forward to hearing what new and twisted ******** they would come out with....
Bill McDonagh: Steinman, I know Medical Pavilion is your manor, but you might want to cogitate on this: ocean water is colder than a witch's tit....
Sander Cohen: The Wild Bunny, by Sander Cohen. I want to take the ears off, but I can't. I hop, and when I hop, I never get off the ground. It's my curse, my eternal curse. I want to take the ears off, but I can't! It's my curse, it's my ******* curse! I want to take the ears off! Please! Take them off! Pleeeeeeease!
Sanden Cohen was a memorable character, as was Dr. (Papa) Suchong, and of course Ryan and Atlas ...... oh and Steinman:
Steinman: Four-oh silk and ...done.
Nurse: The nose looks terrific, Doctor Steinman ...Doctor?
Steinman: You know, looking at her now... I didn't realize how much her face sags... Scalpel...
Nurse: Excuse me?
Steinman: Scalpel!
Nurse: Uh, doctor, she's not booked for a face lift...
Steinman: Let's just come in here and... *starts whistling*
Nurse: Doctor... Stop cutting... Doctor, stop cutting... Get me the chief of surgery! Get me the chief of surgery NOW!!!
Who was there in 2 ..... Tenenbaum was there early on, then vanished without a trace - bit strange that, really could have done with seeing or hearing from her further on in the game

There were 2 brothers, both of which i killed without realising i was fighting them!! Oh and god almighty, there was that Lamb woman who by the end of the game was really getting on my nerves ... just kept coming out with the same old boring crap. And finally that bloke who was guiding me, no idea what his name was, just that he looked like someone i used to work with
Just lacked atmosphere and humour for me. Graphics wise, i like the engine, it works! If it aint broke, dont fix it!
I wouldn't be surprised if the main reason they use the Unreal engine is that it runs well on the xbox and looks good on it. I played the HL2 demo on the 360 the other day and it looked bloody hideous!