When placed near crevices, cliffs and water, the normal concrete walls have these little extensions that pop out, attaching to these side environments and providing supports. Alien Walls does this, but doesn't recolor the "supports", leaving them as their original gray coloring. Also, if you place the four walls side-by-side as a squared "double wall", their inner space doesn't fill in like their supposed to with normal walls.

These are minor issues, but they are not particularly visually appealing: https://i.imgur.com/vzyyysp.png

Edit: Adding "Gates" with a red/yellow stripes would be a really nice touch, too.

I've update the images (re-colored vanilla images, like I had done before) and decided that I didn't want the hybrid walls to connect to other walls, or have the gaps filled in between hybrid and other walls. I had tried it with that enabled, and decided it didn't look good, and the gap-fill was inconsistent.