> However, we still don’t know what they do with the state. Do they modify it, or do they only read it?

   var newState =
        drawManuel(
        drawBackground(
        processInput(state)));

I don't see how this makes it more readable. I still don't know which functions actually modify the state. This is what I imagined the result to be:

    var newState = processInput(state);

    drawBackground(newState);
    drawManuel(newState);