While I had a great time with a group of five yesterday (in addition to some enjoyable two-player sessions of Metroid and Zelda), today was a rather fun set of one-player matches. The game is well-positioned for short, casual gameplay sessions: in a couple of hours of play, the "Double Coins" feature pushed me toward certain games at just the right time, and the Miiverse integration finally working as intended has really charmed me. The lack of integration with other social networks remains a glaring omission, but there was something really appealing about being able to see other people struggling with the same issue or nothing more infuriating than seeing someone gloating about finishing (and yes, both of these came during Donkey Kong's Crash Course). It creates a competitive, collaborative environment where you immediately get the sense that you're not the only person playing. It may not be a "leaderboard" in the traditional sense, but the casual feel nonetheless implies the kind of interaction which fuels continued play on games that could tire easily.
Cleared F-Zero's first 12 levels during this play session (unlocking additional courses I've yet to be able to reach again, although only once was this caused by calibration issues), in addition to setting personal bests in a number of different single-player titles. I don't know how long that'll continue, but it's a good starting point, and the immersive of this play session surprised me (especially after the central plaza was so barren yesterday).
