Wolfenstein 2: The New Colossus opens with BJ Blazkowicz in even worse shape than he was in at the beginning of The New Order. That's presumably the result of the conclusion of that game (major spoilers through that link, by the way), which as Bethesda's Gary Steinman notes in this "Can't Stop, Won't Stop" video left players uncertain as to whether BJ survived the experience.
Obviously he did, but in the opening segment of Wolfenstein 2 he's confined to a wheelchair. Fortunately, his arms are still working okay, so he can still do his thing with the guns. And it's not as though he's immobilized: He just has to go about his business a little differently.
"I think the key for us was allowing the player basically the same freedom as when you are on your feet, so you can basically have full movement even though you are in the wheelchair," executive producer Jerk Gustafsson says in the video.
"And I love that aspect of BJ's personality as well," creative director Jens Matthies adds. "Because he is, essentially, totally physically broken at this point, but there is nothing that will stand in his way of killing Nazis."
"He gets things done," Gustafsson says. "As long as there are Nazis in the world, BJ will keep busy."