I don't know if this is the point, but having only one intended playstyle for either protagonist is quite limiting/boring in my view.Isnt that the point through?
Play Ian side as a dating simulator,play Lena side as corruption simulator.
Also, i really don't buy the whole "corruption" angle from Lena's side -- does anyone seriously think that having vanilla sex with Roberts or Mikes, or getting back to her ex-boyfriend is "corrupting" Lena in any manner, when she has already engaged in water sports with her college professor some few years back? She is simply hooking up, like any normal girl who isn't in a relationship would. Or maybe cheating on her clueless boyfriend if she gets together with Ian, but this, too, has as much in common with "corruption" as milk toast.