According to Official Guinness Records,
The longest videogame marathon on a virtual reality game system is 36 hours, 2 minutes and 16 seconds and was achieved by Jack McNee (Australia) in Sydney, Australia, from 1 to 2 April 2017. Jack played Tilt Brush for his entire record attempt on his virtual reality system.
For a complete list of 2017 records, please visit 2017 Guinness Records in Australia.