This chapter contains the bet the future boss battle; which is the Five Kages vs Madara Uchiha. It also houses the Last battle boss battle; which Naruto vs 6 Jinchurikis( Can all 6 or just 3), 6 Tailed Beats (2 at a time), and Tobi. There are a lot of fights, and almost no chances where you can heal.
This doesn't unlock right after the final boss or after the credits roll. You will need to do something in free-roam after the credits are done. Mine unlocked after leaving the village, some people have unlocked it after accessing the ninja world timeline as well.