11月12日に遊べるのはシングルのキャンペーンモードのみ
マルチモードとPS4とPS5のクロスプレイは2020年予定に延期（パッチで後日実装）


https://blog.playstation.com/2020/11/06/online-multiplayer-comes-to-sackboy-a-big-adventure-later-this-year/

We’ve made the difficult decision to delay the full online multiplayer functionality within Sackboy: A Big Adventure.
The team have been working hard to ensure that online is the very best experience it can be for players and we just need a little more time to get it right
so you can enjoy it to the fullest with your friends and family.

Online multiplayer functionality will instead be coming via a patch by end of 2020. (Account for PSN and internet connection required.)
This patch will also include:

Cross-generation multiplayer where PS4 and PS5 users can play together
Game save transfers from PS4 to PS5**