Seems like very little was changed since beta. The only difference between these patchnotes and the beta patchnotes are the 4 points in under Audio, the rest is basically copy pasta.

Edit: oh and the sneaky removal of this line:

We are open to feedback on this issue [boss walls]. It’s part of the reason we are releasing 1.2.1 as a beta. So please let us know how the new pacing feels to you, especially if you enjoy speedrunning the game.

Despite the huge outrage about boss walls, seems like you’re not really open to feedback after all.