RTL Biathlon 2009 is a simulation of the biathlon winter sport. Like the real sport, it is basically divided into two sections: skiing and shooting. During the skiing sections, the player steers his athlete into the correct direction and watches his stamina. In the middle of the screen is a power bar which gets filled by holding the assigned button; if the bar is too low, the athlete gets slow, and if it is too high, he gets tired.
The gameplay requires steady button pressing to keep the power bar as high as possible during skiing sections. The shooting sequences are also challenging, with a wobbling cursor that makes aiming more difficult. The player can hold his breath for a short time to steady his aim.