Bioshock really hit home for me as a video game on it's own as well as a series for one main reason: it's the first game that made me care about the characters in a genuine way. I could never bring myself to harvest a little sister. I just never could, even knowing the additional ADAM I'd have collected. Of course it wasn't really necessary anyhow, but still...I felt so sorry for those girls, and I couldn't bring myself to do such a horrible thing to them. Aside from that, the atmosphere was very cramped which is something I personally like in horror-genre games, along with the fact that you were in the watery depths of the ocean, where no one could hear you scream. The gunplay in the game is fantastic as well as the diversification of your enemies and the ability to research them to become a more formidable foe against them. The relationship between the gatherers and guardians also just made me really happy, even knowing it was heavily mentally conditioned, it just kind of warmed my heart to know the lengths Daddies would go for the Sisters' safety.
Aaaaand my heart melted when I got to the ending (Good, of course).
I also liked Catherine because it almost awkwardly so hit a little too close to home. Not the cheating situation, as I've yet to be in a relationship at all, but more-so the general indecisiveness of the main character kind of leading after my own issue with it, as well as his ideology that easy is best and that the comfort zone is the safest. I'm not afraid to admit that I stay in my comfort zone because I'm afraid to come out, and this game kind of made me confront those feelings head-on.