Time to have a go at this.

From 2K games comes the return to Rapture, the dystopia created by Andrew Ryan. See also: full price expansion pack, "new" features that should have been in the original, and bugs! bugs! bugs!
<spoilers ahoy>
You play this expansion pack as an early prototype big daddy - that's right, attentive one, just like one of the least entertaining closing segments of the original. Also, your plasmids are largely the same, as are most of your weapons. On the plus side, you now get the Big Drill (tm), only (seeing as it's a prototype and everything) you can't use it for more than about 10 seconds without a refill. The enemies are pretty much the same as episode 1 save for three: the Brute splicers (the Tank, from Left 4 Dead), the Big Sisters (skinny big daddies on illegal drugs) and the other prototype big daddies (nerfed and slightly camp looking big daddies).
Plot wise, there's more of the same ho-hum moral imperative. Do you save or harvest the little sisters (yes, they're still there, yes, they're still annoying) for Adam? How do you respond to the (very small number of) moments where you can execute or spare an NPC who deserves a thorough spanking?
Security cameras, turrets, and research cameras are all present and correct, as are the numerous voice recordings acting as back-filler for the plot. Splicers are still deranged, theres still an omnipotent voice in the sky (except its a woman!) and there's still a grating voice in your ear (another bloke with a dodgy accent). Rapture looks just like it did in the first one, except we no longer have the clever bits like Sander Cohen.
Unlike the first one, you don't get to harvest/save little sisters immediately after laying the smack upon their associated big daddy. In order to get at the adam, you have to plant them on adam-rich corpses and then fend off the inevitable waves of incoming splicers until they're finished drinking their organic Sunny-D. For reasons that we'll simply call "deus ex machina" (see also: making arse-biscuits up on the fly), these little sisters aren't immune to damage, and your Big Daddy armour is about as effective as damp sponge.
Bugs, bugs, bugs. We'll ignore the fact that on first loading the DVD-ROM, "autorun.exe has performed an illegal operation" - details, amirite? For me, the major annoyance was that the game is simply incapable of remembering your mouse settings. Every-fricking-time you load, it resets your mouse sensitivity to "spaz", requiring you to hit escape...control options...apply...back...back before continuing your electric videogamery. That might not sound much, but when the game throws you into a big sister fight when you're holding nothing more than a soiled tissue in your armoury, quickload becomes your bestest fried. The forums (angry Internet men ahead) are full of the usual righteous storming about law suits, bugs and the general crappery of the QA team, but this is a console port (it still tells you to not turn off your computer when saving, for God's sake), so you pays yer money and takes yer choice.
Securom is still there, mod tools are not (tho' reading the license, it basically states that if you did create anything, you waive all rights (moral and legal) to your works for ever and ever, amen). Disk check? Check? Online authentication? Check. Games for Windows Live!!!!!! Checkity check check. The usual crap applies.
Overall, there are worse ways to spend 4.5 hours of your life; Hypnotising a big daddy to fight a big sister whilst you stand there stroking your mustache? Hell yes. But full price? No. Wait for it to hit the bargain bins, and for it to get properly patched.
Finally: Multiplayer. Don't.
win3k