User blog comment:Willbachbakal/My BioShock Sequel Idea Dump/@comment-1671655-20100501163814

Rapture didn't sink. Only Fontaine Futuristics and Persephone. The rest is intact.

I personally like Alek's idea, but I would like to expand on it. You play as a rookie special forces agent who is part of some elite squad. Early on in the game, you are separated from them after an attack by splicers. You must then splice up and fight through Rapture alone.

However, towards the end, you find that your former special forces have all grown addicted to splicing and have turned on you. Imagine fighting enemies with guns, military training and plasmid powers.