2D Character Animations

Hey everyone, I have a question about an upcoming game called Enter the Gungeon. I was looking at their character animations and how fluid their character animations were, particularly the character rotation. Anyone with experience on this would like to enlighten me on how this can be done?

Just took a look. There is no trick or technique, it just a good animator. The simple answers to how they do it is… Skill. Keep practicing or find an animator to help you out.

What Zombiegorilla said.
That are simply frame by frame animations, no special stuff involved as far as I can tell.
If you want smooth animations but with less effort than typical frame by frame animations, you could try bone based sprite tools like Spine, or look into the approach that Zombiegorilla wrote down in the sticky of the 2d forum.