Space Crusade - Wall tiles and double door sprite (Patreon)

Pretty straightforward. This overhead projection style is well explored in games like the Chaos Engine by the Bitmap Brothers. The challenge is to make the wall tiles low enough so you'd still be able to see and select a unit underneath My main inspiration for the door junction tiles was the staple in tabletop wargaming Hirst Arts sci-fi molds catalog; http://www.hirstarts.com/molds/moldssci.html Check out the three making of gifs attached