From publisher website, December 2013:
Why the new name? While a lot of people enjoy PEP as it is, over the years lots of other people have told us they just don’t like the name of our game. In some cases it’s kept people from trying the game or sharing it with friends. So now we’ve decided to make the same game available under a different name. Now everyone can have the version of our game that they prefer.
Will there still be a game called Panty Explosion Perfect? Yes! Panty Explosion Perfect will remain available as booth a PDF and book. Tokyo Brain Pop and Panty Explosion Perfect will exist side by side. The sales information for each game will include the words “This game is also published under the name X”, along with a link to this post.
Why change the name now? Matt and I have resisted the idea of a name change in the past. Both of us like the name Panty Explosion and feel it suits the game well. At the same time, lots of people have told us that the name really has kept us from trying the game or sharing it with friends. So we’re listening to those people, and now with the name barrier removed we’re hoping everyone can enjoy our psychic school girl game.