According to our patron lord Googlix, the plot of this game is thus:
1. Guardian Angel accidentally shoots boy with a "Love Arrow"
2. Guardian Angel must now protect boy from hundreds of swooning girls.
While I'm generally not a fan of "lol japan is dumb" type videos the combination of the stated plot combined with what the game actually looks like produces some kind of space/time paradox and not even physics can predict it's result.