A fantastic experience that, as many have said, is greater than the sum of its parts.
What is it that makes Bioshock so fantastic? It really is the combination of everything the game offers combined. Nothing alone stands out as being mind-blowingly amazing, but everything is packaged to near-perfection and the whole experience is just awesome. The graphics are terrific, though there are some bugs here and there, such as dead bodies convulsing oddly. One thing I was pleasantly surprised to see was a lack of Bloom effects. Sure there was some here and there, but these days, games (like Gears of War, Burnout, Need for Speed, etc) just dump the environment full of Bloom along with a brown tint and it just comes off sorta weird. It's pretty, but just a bit odd... Like since when was the sky brown-blue tinted? Bioshock definitely does not do this. I think the only area I noticed any real Bloom was in Arcadia (the underwater forest area) which is supposed to have a surreal, majestic feel to it. The weapons and plasmids look great and you can see the upgrades you apply to your weapons which was an excellent touch -- from some added gears on a shotgun that spin and make the shotgun fire faster, to a makeshift battery pack modified onto the Grenade Launcher to make it do more damage -- they all look great.
The sound is another great aspect of the game. There's something about fighting 4 or 5 Splicers with 1940s music in the background. I dunno, it's just cool. But old school 1940s radio isn't all there is. No, there are plenty of creepy mood-setting tracks that come on at just the right time to give you this feeling that something is gonna jump out and start beating on you. They really keep you on your toes with the unpredictability -- a lot of the times you get a feeling of forboding and tip-toe along waiting for something to jump out at you... nothing does. And then you let down your guard and... yeah. I'll admit I've jumped a few times. The sound effects are all well done, as well, but the best thing about Bioshock in the sound department is the voice acting. Amazing work. Atlas sounds really authentic and conveys his emotions perfectly. Andrew Ryan also sounds terrific and you really get the feeling you're listening to a megalomaniac that went a little too far. Combat-wise, the game doesn't fail to impress. They really give you a LOT of options in how to deal with foes, although I have to admit I just stick to the tried and true "One Two Punch" -- Shock em then hit em over the head with a wrench. Though I'll often use a shotgun as well. That being said, there are plenty of other ways to deal with enemies, such as hypnotizing a Big Daddy to protect you, hacking cameras and machines and having them fight for you, setting up traps that take out the foes, turning foes against one another, freezing foes and shattering them (but you don't get loot if you do that, but it still helps in a lot of cases), picking up things with telekinesis and launching them at foes (you can light things you pick up on fire for an added punch), setting up decoys the enemies go after while you sneak up on them and take them out from behind... There are a ton of possibilities. My only minor peeve with the combat system is the reload time for plasmids and some of the weapons. I've found myself switching from Plasmids to Weapons just as a reload was about to end, only to have to do the full reload again when I switched back. It's kinda silly see my character injecting himself in the arm 4 times with EVE before actually getting any restored. That's really more the fault of the player than the game though; I just have to get used to the reload times, which while frustrating sometimes, are realistically timed, such as the character injecting himself with a needle, pushing the fluid into his vein and then removing the needle.
As for the story... This is probably the best part of the game in my opinion. It's as ingenious as it is insane. You start off knowing absolutely nothing other than "Rapture is a city underwater created by a guy named Andrew Ryan", and as you go along you learn bits and pieces of information through audio diaries, talking to Atlas and Andrew Ryan (along with a few other characters), and by just bearing witness to what has become of Rapture itself. Each new piece you discover makes you want to discover more and draws you further into the experience. The only thing I dread about it is the fact that I know it has to end. No length would be long enough so inevitably I'll be left wanting more and feeling like the game was too short. I have a feeling I'm near the end as it is... but averages say 16 hours which is actually really good for a FPS. Anyhow, the story is just... indescribable really. My favortie character so far would have to be Cohen. The whole story arc involving him was deliciously twisted.
Is Bioshock difficult? Hell no. Why can I say that with such bluntness? Because it seems that they went to great lengths to make the game easy. Which is sort of disappointing in a way, but at the same time a godsend. It's nice that you never find yourself getting so frustrated with a point that you just wanna throw the controller down and quit in frustration, but on the other hand, there is no real sense of accomplishment having defeated some of the tougher mobs. First of all, you can save anywhere, so you can walk up to a Big Daddy, save right before you blast him, then get into a fight. Now, let's say he kicks your ass.. you come back to life at the nearest Vita-Chamber, with all of your ammo, First Aid packs etc that you had before you died, and better yet the Big Daddy is left with whatever health he had just before killing you. So if you had taken him down to 50% before he died, you can med up, buy new items, then go at him again, with him never having healed. This can be done with almost any fight in the game, including scripted fights (eg. Defend X place against waves of baddies) and bosses. While this does make combat seem sort of trivial, it certainly keeps the game flowing along at a smooth pace. It would have been nice if Hard mode limited the number of times you can be resurrected at a Vita-chamber, to actually make it harder than just mobs having more health and dealing a bit more damage, but oh well. Aside from the combat being fairly easy, the game gives you plenty of hints -- a map with a big Goal Mark, actual hints that tell you exactly what to do, and a big arrow at the top of the screen pointing where to go (which can be turned off, thank the gods). I really don't follow those though, and thankfully they're not so intrusive that I feel I am forced to read them. It's more enjoyable exploring the areas, finding the extra tidbits of plot (along with secret plasmids and such), and taking in the scenery that would otherwise be missed following all the guidelines and hints. But it's nice to know the system is there for whenever you just wanna move on and are either done with exploring the current area, or aren't in the mood to do so.
Is there any replayability to Bioshock? Definitely. There's the big choice of either harvesting the Little Sisters or saving them. This plays a key role in the outcome so many people, myself included, will want to play through again to find out what taking the other path leads to. It's a shame there aren't more choices to make, as "making choices" seems to be a focal point of the storyline, but I don't see it as a glaring issue that needed to be addressed. Aside from the choice to harvest or save, another great reason to replay it is to find all of the audio diaries and extra little areas that you are more than likely to have missed the first time through. Final verdict -- Bioshock is an incredible experience. While not overly challenging, it's entirely fun and enthralling. While there are a few bugs and oddities, the game's execution is near-perfection. Bioshock is must-have for anyone who likes first person shooters. Even if you're not a fan of FPSes, if you like really deep, involving plots, I'd say check it out.