You drive the Snow Cat around to try to reach a target, while collecting coins as you go. You can go into boat mode to move on water. You must blow into the microphones on the DS for it to move though. In another mode, the Snow Cat grows a plow which helps it destroy obstacles. You can also use just normal mode too. To change modes just tap on the Snow Cat with the DS Stylus Pen. Crashing into things will make you lose fuel. Logs and Snow Drifts are the only two obstacles that can be removed with shovel-mode and not take damage (lose fuel). The maximum amount of coins that can be gathered is 260.
In one mission, your penguin says "Wow, I thought that thing drove off the face of the island!" This is a reference to the room in Experimental Penguins called Crash Site.
The penguin driving the Snow Cat is red no matter what your color is.