I said minimal, not zero. To use your Arkham combat example, you do need to build the character animations, but you don't need to build the Arkham city environment in which those combat animations will eventually take place.
To give a visual example, in Street Fighter 5 there's the training stage, which is very simple but ideal for testing character animations and game mechanics. If you were developing Street Fighter 5, wouldn't you build such an environment first?
http://media.eventhubs.com/images/2015/07/07_betapics02.jpg
