Critiquing as part of Weekly Commenting at ProjectComment
I enjoy this very much. The main blue color gives this cathedral an icy feel, and this is accentuated by the watery patterning on the nearer columns and ceiling. The way you have trailed off the bottoms of the edges in wavy, icicle-like lines enhances that tone. In contrast, you have created the washes of pink color that start at the front windows of the cathedral, so that the church windows are radiating a warm light that slowly changes as it moves across the roof. I think that makes the viewer want to lean and yearn for that end of the cathedral.
The structure itself is very well done. The lines of the ceiling are very smooth and your lighting of the columns and architectural features is wonderful. There is a very slight unevenness to the centerline of the roof that puts the perspective a bit off. Similarly, the curvature of the ceiling appears to become more shallow toward the front of the painting. Neither of these are highly noticeable at first glance.
I think it would have been nice to define the closer columns on the left side more deeply. The vague way those columns are painted in contrasts a bit too much with the dark and detailed bases. The almost seem to disintegrate a bit in the middle, where I would expect them to be strong. The same with the right edge around the oval face on the closest base structure. It gets a bit fluffy and fades out when it should be the most clearly defined object, closest to the viewer.
Another area that looks a little bit off is the line of pink to the right of the central window. I would almost expect a third window three, so not sure if there was a wall there in the architecture or if the paint got away from you? It is the only colored portion that extends to the floor, and it goes far below the next window to the left.
Overall, you've captured a very interesting rendering of this cathedral, making it appear ethereal and filled with light, but perhaps cold and empty as well. It's beautiful like a winter landscape--enchanting to enjoy for a short while, but not somewhere you would want to stay for too long.
I hope some of my feedback has been helpful, and please let me know if you have any followup questions or comments.