The bug report link of the Pro Version page brought me here, but the title says "Lite Version". Probably just a minor mistake, but I'll report my bug anyway:
So it seems like you can't use the step modifier for floor 2 and beyond, because it just creates steps on floor 1 instead. I don't really know if this is a bug or if it was intended, but the other floors wouldn't make much sense that way imo.
Also there seems to be something wrong with transparency effects. I imported the same texture twice - a normal one and one with only 50% opacity, for glass blocks or something like that. The transparency seems to be irregular though for unknown reasons, because there doesn't seem to be a pattern in which they work or not. It's kinda hard to explain, so I recorded a short video to showcase that problem: