A brief summary of my experience with Bioshock to date.
Firstly, installation - this worked fine for me, but the game must be activated each time it is installed via an online registration process. Internet access is required. There is also an auto-patching mechanism that updates the game to the latest version as part of the install - this took around 5 minutes for me on an 8mb broadband connection. I understand some people have had difficulty with repeat installations. At present, it seems that customers are limited to five installations per purchase, although supposedly a credit is given for each time you uninstall. This credit system appears to have gone awry in some cases, but Take 2, the publisher, looks to be making appreciable efforts to deal with issues as they arise. Ultimately if you intend playing on more than one machine, or you have a habit of uninstalling and reinstalling, bear this in mind.
Once installed and activated, all ran smoothly until just after the first introduction movie, when the sound almost completely died, to be replaced by strange clicks and pops. I gather this is another issue that many buyers have experienced, and it seems not to be related to any particular model of sound card or chipset. I solved it by switching off "reverb" and "EAX effects" in the options menu - a bit of a shame, but ultimately not a huge loss. There are other fixes being posted on the internet if this doesn't work - and it doesn't seem to be a problem for the majority of buyers.
Technical issues resolved, I cracked on with playing and was stunned. This game has atmosphere in spades and feels more like an interactive story than anything I have yet experienced. The story in question is entertainingly bonkers - a mad scientist's vision of a utopia under the seas gone horribly wrong. The utopia in question, Rapture, is a highly stylised art deco metropolis rendered with stunning graphics and filled with perfectly judged sound effects and music. I haven't felt so engrossed in a world since Half Life 2, which has a very different style but similar overall feel (in the sense that the game is fundamentally linear, but it just doesn't seem to matter).
Probably the standout element of Bioshock is the ability to modify your genetic make-up to develop new weapons and abilities - for instance, early on you gain the ability to fire lightning bolts from your hands, which can then be used on a simple level to stun enemies, rendering them more vulnerable to a solid whack with the wrench, or on a more strategic level to electrify water and take out multiple enemies, fry electrical devices, or enrage the hulking guardians of the city, the "Big Daddies" and goad them into attacking other bad guys. Later on you can adopt more macabre "plasmids", like the ability to fire swarms of bees, and passive skills like the power to tap into electronic devices. I would echo other reviewers' cautions - this isn't a game for kids or the squeamish, as it can be pretty bloody in places and some of the themes dealt with are controversial. For instance, the substance that enables you to develop the above skills ("adam") is harvested by "Little Sisters", screwed-up children that wander the city tapping corpses for their genetic material. Your choice is whether to free them from their gruesome task or kill them to harvest their adam in turn. At least the choices you make have an impact on how the story progresses, and playing the good guy can lead to some welcome surprises!
A quick note on performance - on a Core 2 Duo 6600 with 2GB RAM, an Nvidia 7950GT (512mb video RAM) and X-Fi Music card it runs nicely at 1280 x 1024 resolution with all but a couple of settings on high. Anything bigger than a 19" monitor and an 8000 series Nvidia or equivalent Radeon card is probably the order of the day.
Basically, once teething troubles are dealt with (one star lost for these) it's a gripping, beautiful, atmospheric interactive movie that plays like a dream, given a decent system. Thoroughly recommended.