Show me an indoor enclosure for gorillas anywhere that can support living plants in with the animals.
Of course it is a "set piece". So is every exhibit, by definition. Some are better crafted than others. I'd place this one somewhere between the purely "utilitarian sets" of Howletts et al and the elaborate and detailed "realistic sets" such as Woodland Park, Animal Kingdom and the Bronx.
The only vegetation I can see here is grass. Gorillas will rip up and eat everything/anything in an indoor area where they are confined many hours per day. Only well established clumps/trees in oudoor areas will be ignored because they've got far more room/choice what to browse on outside.