Nanaca Crash is a flash game in which you control a girl (named Nanaca, I think) on a bike and try to smash into this guy (named Taichi, I think) and the goal is to launch him as far as possible. The game is played entirely with the mouse button i.e. you don't have to click at any particular spot or move the mouse, you just have to time your clicking. Pressing the mouse button sets the angle, and releasing it sets the power.

Once Taichi is in the air, you still have some degree of control over the action. When he's between 10 and 3 meters off of the ground, you can click again to strike him again. If he's currently moving down, the "AERIAL" word will turn red, and when you click, you'll launch him upwards. If he's currently moving up, the "AERIAL" word will turn blue, and when you click, you'll launch him downwards. You can only launch him upwards 3 times, but you can launch him downwards an unlimited number of times (though you'll have to let it recharge after each use).

There are people along the road, and they do different things when Taichi collides into him. On the right side of the screen are icons showing who the next three people on the road are. Above that are five girl portraits which are "bonus" targets. If you hit one of the bonus targets, the word "special" will appear for 0.7 seconds. When that happens, click the mouse button and something good will happen. Trying to strike bonus people is the main reason for trying to launch Taichi downwards (i.e. using the blue aerial strike).

Avoid that damn green girl with glasses. She just stops Taichi. Most of the other girls seem to boost him further, and the guys seem to either slow him down, or change the angle he's travelling at.