From what I understand in an introduction by the author, Anthony Burgess, this novel ends at Chapter 20–at least for lily-livered 1961 America. Without knowing what that edited out by the publisher last chapter (21) will bring, let me remark on where the story leaves me had it ended here.
Alex, no long loved by anyone, used by both government and rebellion as a poster boy for crime-stopping measures by destroying freedom of choice, decides to take his life and unfortunately is thwarted by his selection of too short a building. But whatever has been done to him while he lies in a coma has negated the sensations of pain and nausea that were part of the "cure." The government has won, or so they think, and the rebellion of those opposed to the process of which he had been a victim have been beaten and jailed. Of course, his own tendencies to slash and stomp have never been changed, so now he’s free to do whatever he pleases. Here, he has been assured that he has recovered, and he asks that they play for him Beethoven’s Ninth Symphony, his favorite.
Oh, it was gorgeosity and yumyumyum. When it came to the Scherzo I could viddy myself very clear running and running on like very light and mysterious nogas, carving the whole litso of the creeching world with my cut-throat britva. And there was the slow movement and the lovely last singing movement still to come. I was cured all right. (p. 205)
Leaving it here, we see a circle that Alex has come through that ends where it began. Freedom of choice is inviolate, and so is the power of the government to control people’s minds. They are of course taking advantage of the opportunity to quelch public opinion by "curing" Alex of what had been done to him. What their plan is for controlling his later behavior is still a question.
But, Alex is free.