The game length of Hollow Knight varies depending on the type of playthrough:

• Main story completion takes about 27 hours on average.
• Including main story plus side content raises the time to around 42 hours.
• For a full completionist run to obtain 100% of content, players typically spend about 64 and a half hours.

Player experiences vary, but most first completions range roughly between 20 to 30 hours if just focusing on the main game and time can extend significantly if exploring thoroughly or aiming for 100% completion.