After some experience in a couple games I find that the first couple players that jump out ahead in the neptunium race tend to get overtaken later in the game pretty easily. This leads to naturally some bitterness but it also introduces the idea of the "kingmaker." The thought of, "Well if I can't win, I'll do whatever I can to make this guy win."
This can lead to gifting of mines, specialists, drillers etc.
Now to me, there is no such thing as 2nd or 3rd place. I feel like the presentation of that gives users hope that maybe I can at least get second place. But When you're mining Neptunium to build an aparatus to take over the planet, at the end of the day, that includes mowing over 2nd place. Seems like it's an all or nothing game.
Is this the case in your games? Would it benefit the game to display that all the others have lost and there was only one victor? Or is it still left in the hands of the diplomat who convinced the other player to help him win?