The first key concept that I will describe within Bioshock is how ethic and dualist systems make games more interesting, and provide depth which helped make Bioshock a successful game. Under Bioshock's narritive exterior lies an well developed gameplay experience, but there are many choices that a player must make within the game that may determine the overall gaming experience for the player. For example, a player must choose to harvest or rescue the "possessed" little girls that patrol the building's of Rapture making the character either good or evil. By harvesting them you take all of the Adam inside of them and use it to upgrade your body (which can make the game somewhat easier) however, the girls are unable to survive the process. When you rescue the girls you take a small bit of Adam from them but they easily survive the process, and you are promised to recieve a reward for saving the girls later in the game. I didn't play through the entire game but I would expect that many of the consequences coming from the choices made by the character during the game will come to fruition toward the end of the storyline. These different choices within the plot will assuredly increase the replay value of the game because a player can get a different feel from the game each time they play. RPG style upgades found throughout the course of the game also supplies an added depth that many ganers are looking for these days.
The second key concept that I would like to focus on from our readings is that philosophical questions within a game provide the means for growth that will come from games in the future. Personally I believe that without Bioshock's philosophical questions (which somewhat parrallel our own cultural thoughts and ideas todayth) would be throughly enjoyed by player's because of it's strong first person shooter element and the RPG style system that allows a player to spend hours at a time developing a character. The first Bioshock's gameplay is extremely fluid (feels natural) and gives a wide array of different weapons that a player can use to tear spicers apart. Also, scary images (like shown in the picture above) are loved by many gamers because fear can provide an emotional stage that keeps a player constantly engaged and interested. Beyond the philisophical side of the storyline lies a basic good and evil feel to the plot (Ryan is a man that has gone crazy in his quest to create a world without boundaries, and the player is an innocent man caught within the choas that's occuring inside of rapture. So whether you become good or evil you still manage to save yourself and perhaps the future of the planet (I might play through the game just to make sure that this assumption is correct).