It is, but it's by far the trickiest to get to. We'll probably adjust requirements down the line at some point, but also as mentioned elsewhere, we'll likely have the CGs just unlock when finishing the game, once we have actual endings.
It's a work in progress after all, so it still needs some refinement in places of course. But priority for now is first getting the story in and all that, then we can worry about these other things.