Bioshock is immersion, literally.
The gameplay in Bioshock is your standard First Person Shooter variety gameplay, with some Role Playing Game elements mixed in. It consists of finding weapons, interacting with people to advance the story, and most interestingly, genetic modification. The real ingenuity behind Bioshock is the story, and the plasmids. Plasmids are tools made from "Adam", that give you magic like abilities. There are many abilities to be had, some active and some passive. For example there is a plasmid that grants you the ability to set a foe ablaze with the snap of a finger, or freeze them solid with the same ease. There are passive abilities as well that can make you stronger, or faster, or better able to hack terminals, robots, safes, and turrets, among many other things. These abilities rely on what the game calls "Eve", which you find in injectable syringes, and nonchalantly stick in your arm. The downside is you can only carry 9 syringes at any one time, and until you unlock upgrades that allow you to have a larger "Eve" meter, you really don't get many uses before you need to use up a syringe. When you run out of "Eve" you can't use any plasmids, but luckily you have many weapons at your disposal as well. Much like your own body, the weapons can be upgraded throughout the course of the game to add things such as damage upgrades or recoil dampening.
During your travels you will often come across audio recordings, as well as be contacted by people via radio, which is how the story progresses itself. This is not a new thing in games, but it serves the purpose well in Bioshock.
Along the way you will encounter a creature created from a female child, called a "Little Sister". Little sisters were created by Rapture's scientists, to harvest "Adam" more efficiently, so that they may further advance their society. Because of certain genetic properties, the little girls are almost invincible, able to regenerate cells instantaneously. Nonetheless, scientists created protectors for these children, in the form of the "Big Daddy". The Big Daddy is presumably a human having undergone genetic modification to make them stronger and faster, and evidently smell bad too. They wear an armor-like deep sea diving suit, and carry large weapons or sometimes a corkscrew device attached to their arm, which is the size of a vacuum cleaner. Don't let their size fool you, they are lethally fast, and do terrible amounts of damage. In contrast, your weapons feel extremely weak against all enemies, even if you have them fully upgraded. You are able to research enemies throughout the game, to receive damage bonuses toward them, as well as other goodies. This research feature is almost a necessity, as even fully researched the enemies can take a huge amount of damage from your conventional weapons. Even the plasmids such as fire do little to harm them. At the third and most powerful stage of evolution, your fire plasmid will stack its damage if used in succession on the same enemy, which still takes up to 10 seconds to bring down a common foe.
By contrast the most lethal weapon in the game is not your super genetic powers, nor your machine gun or rocket launcher. No, your most powerful and deadly weapon is the common wrench. The wrench in combination with your shock plasmid, is the first one-two combo you get at the beginning of the game, and remains your most powerful weapon throughout. You can fire upwards of 80 rounds from a machine gun at an enemy, or you can simply shock them once so they're paralyzed, and simply hit them once or sometimes twice with the wrench; you make the call.
Graphically is where Bioshock shines. The development process had an entire team brought in to do water effects alone, and it shows. Rapture really feels like it is being retaken by the ocean. The water is top notch, but I wouldn't call it impressive. Everything graphically in the same is great, especially the lighting and shadows. The lighting and shadows far surpass the water effects, and serve to immerse the player into the creepy atmosphere of Rapture. This underwater dystopia is brought to life by the light and dark. Something I think the team had overlooked graphically is that water stagnates. Presumably the city was there and leaking off and on for many years, so those pools of water should contain algae, and all kinds of sea life. All in all the graphics in Bioshock are great though, which brings me to system requirements.
Bioshock requires an Nvidia 6600GT equivalent or better, 1 Gigabyte of RAM, and a fairly powerful single core CPU. These requirements are prohibitive for some people, but those of us lucky enough to have higher end computers, can enjoy this game to its fullest. My current rig contains 2 Gigabytes of RAM, and a high end Dual core CPU with a 768 Megabyte 8800 GTX video card, which runs the game very comfortably on the highest graphical settings. The good news is Bioshock looks great even on the medium to low settings, which means many people will be able to enjoy this game. However if your computer is aging, you may want to pick this up for the Xbox 360.
The sound in Bioshock was much understated, and has some minor issues but nothing that takes you out of the same. I am running a SoundBlaster X-Fi sound card, but really didn't notice much in the way of an aural experience. The sound is passable, and not really noteworthy. Things sound how you would expect, with water trickling, the weapons and plasmids having their distinctive sounds.
The high point of the sound in Bioshock is the voice acting. The voice actors did a superb job and are all very believable, adding a very great dimension to the story telling. The audio recordings you find are very frequent, sometimes overlapping the radio transmissions you are listening to at the time, but you can always go back and replay them. I found myself having to do this often, as the game liked to talk during battles where you really can't hear the voices over the mayhem, but it is alright since you can replay the messages afterwards.
This game is worth every dollar, it is a top notch and immersive production, and I can recommend it to anyone. The difficulty level is not prohibitive in the least, and veteran shooter fans will find it quite easy. First Person Shooter fans and people who enjoy a good story will both enjoy this game. The moral choices will give it some replay value, as well as the choices of how you build your character.
Bioshock in the end, lives up to my expectations of being a great game, a decent shooter, and an involving story with characters you grow to know.