Multitask, er... tasks you with performing simple activities at the same time. It starts with a ball on a block that's tilting back and forth randomly. You tap the left and right arrow keys to keep the ball from falling off.
Shortly, a second activity appears, as seen in the pic. Now you have to move the block up and down the segmented chamber in order to avoid the incoming spikes... while still maintaining balance with the ball.
Shortly after that, a third and then a fourth activity is added to the mix. It's a bit like patting your head, rubbing your tummy, playing jumprope and juggling a football at the same time.