The Good
In literature, "star-crossed" lovers are doomed by fate; in TRILLIUM, that may or may not be true (we'll find out in three more issues), but Nika and William are experiencing an entirely different sort of tragedy -- they're entirely in the wrong place and time.
Jeff Lemire exercises an incredible talent for synchronous dual narrative in this issue; not only do the stories line up marvelously with their (inverted) origins in Issue #1, but the panels themselves often line up visually. Carefully-chosen camera angles, coupled with reflective panel layouts, place Nika and William as mirror images for much of the book, even as their stories venture into opposing and unfamiliar territory.
The mirrors aren't quite perfect -- some panels don't line up exactly -- and it's a great visual analogue for what the story is doing. Nika is "unwell" in her newfound modified-Victorian setting, and William is similarly plagued in his unfamiliar future. Everything is unpredictable, there's no clear path to getting things "back to normal," and neither version of "normal" was very exciting anyhow, so maybe they should try for better -- Lemire is keeping us on our toes with this arc, in the best way possible.
Digital readers: you're in luck; the guided-view option on comiXology takes you through the story in correct panel order (zoom out and you'll see what I mean).
The Bad
Colorwork is split this issue, with Lemire taking on the bottom section and Jose Villarrubia coloring the top section. It's a reasonable division, if the work must be split, but it's going to look funny in trade. One of the narratives is distinctly brighter and more solid, while the other is watery and brush-stroked; neither is inappropriate to the work, but it conveys a subtle note of imbalance between the two stories. Since Nika and William are equal protagonists, and neither story commands the issue, the variance in coloring styles is misleading.
The Verdict
I've never been so excited about turning a book upside-down before. TRILLIUM is firing on all cylinders, and this issue in particular is stunning in its perfectly-on-point reversal of Issue #1. The narrative is deeply engaging, the characters are easy to invest in, and Nika and William are decidedly brilliant in each other's shoes. Jeff Lemire is doing amazing things with sequential storytelling, and if TRILLIUM isn't on your pull list already, put it there.