I've only played the renpy version, so this might possibly not be relevant for the original game:
As I wrote in my review, I love how nickfifa manages to keep the girl to stay on the narrow path for so long. Most corruption games have the girl turn slut far too quickly. Here Elena actually keeps saying crucial stuff for a long time: regretting doing stuff, trying to not do it again, it was a one-time weakness, she's not that kind of girl... It's only around day 50 the best parts of the game is over since she's starting to accept what she is by that time.
One thing I would have loved to see is a more extreme schedule: while Nickfifa generally manages to fill each and every day with a new event, the game does settle into a rhythm of ~2 sexual encounters a day. I would have loved it if Elena's days was filled with more and more cocks!
Still keeping her fairly upbeat and happy, but making her sex life take over her life, so during the last weeks she would have days with five or more appointments and maybe a dozen cocks to satisfy that day.
The sequence with the pill comes too late and plays an insignificant role. I love games with the pregnancy risk fetish, and would have loved it if Elena was in any real danger of getting knocked up during the game itself.
Finally, the endings. Just offering endings where Elena chooses ONE man is, frankly, a disappointment. Everything about the game suggests she is the happiest when there's always a new cock around the corner. I would have loved endings where she refuses to choose; endings where she remains "friends" with three or seven or all of the men, and where she never knows who fathered the next baby...
But again, none of this removes the fact the game is a corruption masterpiece.