We are developing a robot that can play Darumasan-ga-koronda game (similar to "Red light, green light" game) with human players. We have developed a method to detect and track the players, to determine whether the players are moving and to actually play the game. A problem is that the system often lost or misdetect the players because the players' posture during a play is different from that when a person is walking. Therefore we propose two improvement methods. The first one is to improve the segmentation of objects using an LRF that works even when a player's arms overlap with the body. The second one is to detect the object that is the most probable as a human body. We conducted an experiment to confirm the effect of the proposed two new methods, and the result proved the improvement by the proposed method. In addition, we conducted an experiment to actually play the game by the robot and humans, confirming that the robot could actually play the game without big problems.