You would be pretty crazy to see the observations made as coming from anyone but Junpei, given the context, except the whole screen thing, even though there are weird little issues of phrasing that don't quite make sense, but if the game was arbitrarily played on two screens, it'd give that bit away. The trick is that Akane's observations are actually happening on one screen, while what Junpei experiences happen on the other.
You are actually controlling a girl in the past named Akane, who is seeing the world through Junpei's eyes. You aren't actually controlling Junpei, as you are led to believe for the entire game, at least, not really. The screen being arbitrarily divided into two halves would give away a huge plot element pretty quickly, if you are paying attention, as well as some smaller stuff.
