How do Frog Fractions and Nier use intertextual knowledge to subvert the player's expectations?

At first glance Frog Fractions (Twinbeard Studios, 2012) and Nier (Cavia, 2010) appear to be a fractions-based educational game and a Japanese role-playing game respectively. One thing these two drastically different games have in common is that they both set themselves up as standard entries in their respective genre and then utilise the player's intertextual knowledge of other games to establish an expectation which they then subvert using techniques that this essay seeks to define.