“Bullet Train” is weird and wild and undeniably bloody, taking audiences on a 2-hour journey across Japan. But if you’re here, that probably means you’re wondering what happens at the end of the line.

After a little over two hours of sudden surprises in David Leitch’s over-the-top action extravaganza Bullet Train, there’s one final surprise: There’s no post-credits scene. That feels unusual in a ...