Bioshock is amazing; it is just that simple.
1) The game is in First Person view, but because of the different ways you can customize your character, you can play it as a FPS or FPSneaker. And you can mix the strategies as much as you want to find your perfect balance between run-and-gun or stealth.
2) There is actually a story going on, with characters you eventually get to know quite well via audio diaries. The inhabitants of the city don't make complete sense until you get more back story. The story also takes a few twists along the way to keep it interesting.
3) The environments are nice and fit the 'war like' feel. They also can be used in the battles such as lighting up oil-slicks or throwing tables, canisters, etc at enemies.
4) This is a single player game. I actually found that a big plus because when you get multiplayer you usually get a barebones single player mode.
5) Just about every play mechanic, including the 'respawning' on death, makes sense in context of the story.
6) Major enemies were people. That's right, believe it or not the boss fights actually felt like you were taking on another buffed up version of the people living in the city. It was nice to be able to fight realistic bosses rather than some super demon that seemed out of context.
But what isn't right about it:
1) You are in an underwater city that despite how many leaks you see, never fills up. In fact massive leaks never cause the water level to rise over a certain level in any specific rooms. It would have been nice if you could drown... or at least something that comes and repairs things. So go ahead, frag granades to the walls if you want, it ain't flooding.
2) The research camera got in the way. Taking pictures of a splicer is not going to make you more effective against them. You are completely customizable, so why aren't the enemies? Let me play the game, not pretend I'm a photographer. It does give you some close up shots of the detail that went into the character design.
3) The language. It wouldn't have been tough to keep the F-bomb out of the game. It adds nothing to the 'feel' that couldn't have been done with language that was more fitting or diabolical.
On to the details...
So you find yourself in an airplane which soon crashes into the ocean. You find yourself in the water similar to the movie castaway. Soon after surfacing you find there is only one way out of the water and that is into a big tower which soon takes you to the city of Rapture. The game introduces the city and its premise as you submerge via a nice movie.
But once you surface inside the city you find it is a little more violent than it should be. You find a radio transmitter and go to meet up with Atlas (talks via the radio), who will fill you in on some more details. Turns out people want to leave the city, but the founder, Andrew Ryan, won't let people leave. Looks like you are stuck down here and have to fight your way out. Atlas is in the same situation.
As you work your way through the city, you will find more audio diaries from the inhabitants that fill in more specifics about what is going on. You also find a weapon, a wrench, which you will have to use until you can find something else. Shortly after you will find what make rapture, and bioshock, such a different game, Plasmids.
Plasmids are basically genetic solutions that 'splice' into your own genetic code an allow you to do some pretty cool stuff. Like electric bolts, like Force Lightning, fireballs, or even telekinesis (the ability to move things with your mind).
There are more than just offensive plasmids though, you soon find there are 'spell' like plasmids, then also engineering, security, and combat plasmids that are passive that change the way your character works and interacts with things around him.
See all those guys standing in the water... don't shoot them, just fry them with electricity. See that big canister, pick it up and throw it at your enemies instead of wasting those bullets. I found myself relying a bit much on my weapons, seeming that is the typical way of playing a FPS, but you certainly don't have to.
You can maintain your ammo supply and health by looting those that are dead around the levels (and those that you 'make' dead). But you also have vending machines around the areas, do remember this is a city aimed at making money, no bars attached, so it actually makes sense in the long run.
You will also run into Cameras, Turrets and Bots. There is a way to get the defenses of the city on your side by hacking them which introduces a 'pipe' game where you have to get a connect pipe from one point on the grid to the other. You can hack not only the defenses but also the vending machines to help reduce prices and make new options available for purchase.
Also you will find Big Daddies and little sisters. They are a major part of the plot though, so I won't give away any details. Let it suffice that if you watch them a little bit you will get the idea.
There are a few different difficulties you can play on. Normal was probably a little too easy for someone familiar with shooters. But if you want you can play on Hard, turn off the assists and even the respawn points which makes things a bit harder. It borders 'easy' for me, but I think it is customizable enough to make it feel less like a trial of time wasting and more of a fight.
I recommend this game to anyone that once had a love for shooters, or prefer their shooters to be more than an online frag fest. I'm not sure people that only love turned based games should try this out, but if there was ever a game to try for people turned off by the FPS genre this would probably be it.