The completion time of Twelve Minutes will depend on your ideas and acuteness. It is also affected by whether you want to see all the endings or unlock all the achievements.
In Twelve Minutes, there are 6 story endings and 12 achievements that you can earn. The time of the game will extend or shorten depending on whether you just want to finish the game or complete 100% of what the authors have prepared. As the game requires observation and cleverness, each player will find their own pace. With this guide, however, you will manage much faster. To complete the game and get all the achievements without any help, you will need about 8h. If you want to complete the main story on your own, you should fit in about 3-4h. On consoles, the time may be slightly longer due to slower navigation using on a pad.