Ok, This is just on a whim, but here goes nothing.
Humans of our world (us) were all invited by a technological advance corporation with a high prestige for video game software. We are invited to try out a new software for a more interactive game (could be Pokemon up to you), but the device either malfunctions, or is a trap, and we are all sucked into the world, prisoner's in this "game" world. The only way to escape: play the game.
Just thought of it right now, but it would be a way to bring all of us into the game itself. However, the idea behind this is that it doesn't just have to be Pokemon. It could really be anything. And the twist is, we know it's all technically "fake", but we try to adapt to the situation inside, no matter what we decide it is.
That's what I thought of, at least. What do you think?