Wargame Terrain - Stackable/Buildable - Sci-Fi

I designed this terrain system for my son's game club for school. He needed something that could be transported and rearranged easily. The height of the walls is 5" (127mm) The walls are about 6" long and 1" wide. It's beefy, but the tolerances are loose enough that it should fit together fairly easily. I've printed most of the pieces so far, but I may need to make further changes. The biggest issue I've run into was printing the walls upside down caused the corners of the floor slot to be rounded too much. I've chamfered the interiors and most should be able to print without supports in the upright position.

The stairs are just over 200mm long. I have to arrange them diagonally on my printer.

Pictured prints show some test parts that have been since modified. They assemble fine, but there are some print settings I need to watch for different printers I use.