with no break whatsoever.... I guess about 12 hours, as a kid with Chrono Trigger.... started after dinner and stopped when I heard my parents move upstairs as they were getting up... didn't want to be grounded =D
Otherwise I don't recall an other time without any breaks ( I usually do 8 hours before I need to go on a break at work :p so I guess that's my average....)
OoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoOoO







