Yoon's talents lie strongly on the writer side, as an author of lyrical, strange, high-concept SF/F in traditional prose formats. She has a proclivity for improbable fanfic mashups. And thus, here we have a short, poetic, lachrymose and opaque piece -- a fragment, really -- about Swan Lake and Klein bottles.
As an Artshow piece, there is not a great deal to do in Swanglass except to try out commands and piece together fragments of story, until you find the thing that ends the game. The writing sometimes works and sometimes is too overwrought to take seriously (">X MOSS Soft and green and vulnerable. Like your heart, once.") If you're not vaguely familiar with the plot of Swan Lake, it'll make very little sense; even if you are, you'll get little more than glimpses.
One of the big problems with more serious IF is how to maintain tone when the player resists it by entering silly or out-of-character commands. This is more of a problem when tone-viable, useful actions aren't obvious. It's tempting, in this situation, to write in snarky dismissive responses, in the same general style as the rest of the game; this works very well for some narrative voices, and quite poorly for others. Swanglass, with its tone of highly-strung, lyrical grief, is not really appropriate for response-snark, but the snark's there regardless. The answers to >EAT SWANGLASS or >COUNT LEAVES are entertaining, but give up too much: you get the sense of the author lampooning her own style. A larger game might get away with this.
In most respects this is like a tiny, puzzleless Moonlit Tower. If you enjoyed that and want more, this will deliver a very small taste, but probably not one that will satisfy.