The first game involved flying across a body of water onto small islands while a timer counted down. Each landing extended the timer briefly, so the faster we flew, the more distance we could cover. The idea of precision flying onto small target islands was reminiscent of Pilotwings or of Super Monkey Ball's wonderful "Monkey Target" minigame, except ... controlled by flapping your arms. In a clever use of the Balance Board's weight and balance measurement capabilities, the game registers the vibrations your arm movements make on the board and translates it to speed of on-screen wing flapping (by a character in what looks like a chicken suit). Leaning forward allows you to fly faster, and you can turn by leaning left or right. We were able to land on one target easily, and we were able to aim correctly at the second island, but we hit the side wall of the tall island and couldn't get high enough in the air to reach ground level. It's important to note, since Wii Fit Plus is an exercise game, that after flying in, our arms were tired.
The next game we tried was the "platformer" level described at the keynote. Basically a series of gauntlets involving swinging wrecking balls, sliding platforms, and jumps, it reminded us less of Super Mario Bros. and more of the diabolical Sasuke/Ninja Warrior show -- not at all a bad thing. In this game, players run in place on the Balance Board, straightening your legs to jump like in the first game's ski jump event. After each successful run, you're put into a harder level.
We also briefly played a snowball fight game, which uses the Balance Board to control a cover system. Your avatar stands behind a barrier, and you can lean out to toss snowballs at opponents with the Wiimote.
Other games available, which we didn't try, included things like skateboarding and "Rhythm Kung Fu." One thing that we'll regret for the rest of our lives, even after the game is out: we didn't try the Segway game. There's a game that uses the Balance Board to simulate riding a Segway. How could we have missed out on that? And how is that exercise? And how could we have missed out on that?