The importance of sketching/roughing out an animation idea can not be stressed enough.
I’ve gone through so many ideas that get scrapped because it would be a nightmare for the player to interact with. Player responsiveness overrides anything that interferes with the flow and action of the character. Press A to jump and the character has to respond immediately. If you’re running and approach an edge to jump over a gap, and the character anticipated the jump every time you’d probably throw the controller through the screen and cry about what you’ve just done.
The following GIFs, not timed out, give me a rough idea of how I want Dr. Mengele to perform his attack. When I interact Lulu attacks him in the level the action could be shit and i’d have to scrap it.

You want to establish the main idea of the action. It could be just a couple of poses but if it establishes the action, that’s all you need. With this guy I drew a couple of breakdowns because it helped me see where I was going. But it wasn’t necessary.

This is mainly for Juan, the programmer and I to get an overall view of the demo. It’s also helped me cut down on the cutscenes and learn more about the main antagonist and how I want to deal with the violence. Finding a bridge that favors more Hitchcock, when it comes to less is sometimes more.