Number One Trophy in Hyperdimension Neptunia PP

At the beginning of your playthrough, your world share is pretty small, but by performing concerts and doing activities from Work, your world share will grow. However, you have to be careful with reaching first place in world shares. In this game, your playthrough will automatically end once you reach first place in world shares, regardless of how far you are into the game, even if you have not seen all story events yet.

At a later point of your playthrough, there will be a limit at 25 %, since all four goddesses will have this amount of shares (if you always stay in your own country). To be able to rise it further, you have to move to another country. Blanc is quite an exception to this rule though. In many cases, she will automatically reach first place, once you reach 25 %. To avoid getting to this, you have to move to another country very early in your playthrough. You can then increase your shares in that country, but the goddess who lives in that country will also try to get shares. This means you can see more Activity events.
You can check the current shares by touching the front screen in the status screen. Once you reach first place in world shares, you will be asked to do a final concert and your playthrough will end.