The pilot reported that the airplane was too high during his first approach to the 2,355-foot-long, 100-foot-wide, asphalt runway, and he performed a go-around. During his second approach, the airplane touched down normally; however, he was not able to stop before the end of the runway. The airplane veered off the left side of the runway, about 100-feet prior to the end and came to rest in a marsh area. The airplane sustained substantial damage to its nose gear and firewall. Examination of the airplane, which included an examination of the left and right brakes by a Federal Aviation Administration inspector, did not reveal any mechanical malfunctions or failures that would have precluded normal operation. Tire marks which corresponded to the airplane were observed to begin at a point that was about 600 feet prior to the end of the runway.