So, I had previously commented on this piece, but now I feel brave enough to do a review.
As more neglected Archie characters and as a neglected couple, it's always interesting to see these two. Wonderful shading, relatively clean lines, and generally excellent color choices make this piece pleasant to look at it and act as a window into the depth of the Archie continuity. Their facial expressions in particular are happy, but wary, fitting the personality of the characters.
From a technical perspective, there are a few things in this piece that really should be lauded. Amadeus' hair and Rosemary's left foot in particular are very well-drawn.
There are a few problems, however. The shading could use one more layer of depth, so Amadeus' arm can be easily distinguished from his tail. Rosemary's dress is formless; it kind of looks like a snuggie. I suspect that wasn't intended. I have a hard time telling what part of Rosemary's body is portrayed toward the left of the image (from which her right leg is protruding), and it seems to end suddenly. Rosemary's hair is a little flat, and the lines in Amadeus' tail seem a bit off near the tip. The bottom contour of the eyes is on the deep side for this art style, and the pale portions of Rosemary's ears don't quite match.
The points docked in vision are mostly because the pose and shading of the piece draws massive attention to what I call the "neck problem," or the relative absence of necks in Sonic character design. I don't question the accuracy here, but the posing and framing of the bodies draws attention to what is probably the ugliest aspect of this property's aesthetic.
There's also something really interesting I want to talk about in this piece, but I hesitate to incorporate it into my actual rating. The grass. Every time I look at this picture, I am struck by the grass. A careful analysis of the strokes, colors, and design choices of the grass and sky here suggest simplicity and a lack of vision, especially the clouds. So why are they so visually striking, creating that perfect feeling of a warm spring day outside? It's because of that simplicity. There's just enough detail to the grass to give the whole scene a sense of depth; same with the clouds. The relative non-realism of them actually shits the focus to the emotional content of the picture, because we don't remember the glint of light on every blade of grass when we go on a picnic. This feels like something one of the characters could have drawn trying to remember this day. It adds a layer of nostalgia, and I never saw this couple together in the comics.
That said, if you're going for a more visual reaction, another layer of shading on the grass with a light color wouldn't hurt. I think it's great the way it is, but what is a critique for if not to explore the potential of a piece?
Overall, despite a few minor technical problems, this piece is every effective at capturing an emotion, and it makes me care about a pairing that didn't really come into prominence until after I stopped reading the comic it's from. In some ways what others might treat like a flaw works for the piece, adding a layer of psychology in lieu of the photorealism many would expect of fanart of a comic that was never photorealistic to begin with.