The monkeys return as they go after their bananas once more.
I only looked at this demo briefly; there were a couple of the mini-game modes available to try. On selecting a game, the character selection screen came up with all four monkeys from the first game, as well as four more, and eight empty slots for even more characters.
Monkey Fight is completely different to how I remembered it. It now takes place on stages, Super Smash Bros. style, with the appropriate running, jumping, and fighting controls mapped to the 3DS buttons, including L&R triggers. Moving around is fairly straightforward -- you go through platforms from the bottom, and when you jump you can stay in mid-air for a few seconds to fight your opponents. Walking around uses the Circle Pad.
The object of Monkey Fight is to collect bananas that generate in various places around the stage. Hitting your opponents will knock bananas out of them that they have previously collected. The controls were a little tricky at first due to the gameplay style, and it's hard to get anywhere just mashing one or two buttons. There didn't seem to be many item pickups, but now and then a golden barrel would appear, which would power-up the player who hit it several times, similar to the Smash Ball of SSB.
This mode wasn't a lot of fun against CPU opponents so multiplayer support will be essential. Then it could be considered as a good distraction.