In video game literature and video game reviews, video games are often divided into two distinct parts: interface and gameplay. Good video games, it is assumed, have easy to use interfaces, but they also provide difficult gameplay challenges to the player. But must a good game follow this pattern, and what is the difference between interface and gameplay? When does the easy-to-use interface stop, and when does the challenging gameplay begin? By analyzing a number of games, the paper argues that it is rare to find a clear-cut border between interface and gameplay and that the fluidity of this border characterizes games in general. While this border is unclear, we also analyze a number of games where the challenge is unambiguously located in ...