What's so demanding in TO1886? The baked lighting? The handful of characters on screen at once? The almost non-existent physics? What TO does, it does great, it's just what it does is nothing to write home about.
To give some evidence to the "not demanding" argument, here you go:
"I would say that a version of TO without the black bars would have been pretty much indistinguishable from the version shipped, as far as performance/image quality"
http://www.neogaf.com/forum/showpost.php?p=191125296&postcount=277
And yes, dynamic GI with changing environments is more demanding than baked lightmaps.