It's coming right along!
The shading on the columns looks great (I always expected you were going to touch them up to make them look like 3-dimensional structures, and the original design was essentially a draft to set the width of the fluting / number of vertical stripes) and I approve of the 4-way gradients. Plus real transparency -- my eyes thank you.
I'm not sure about making the spirals so grey, though. I think a better solution to the high-contrast issue where the white and teal meet might, instead, be to keep the colours and make the transition more gradual... more like the way the circular patterns in Technology of the Ancients (and the Underwater Ruins tileset, default #63 by Zenth) seem to glow.
I took a few minutes with GIMP (and, for anyone still clinging stubbornly to Paint, this is an excellent illustration of how something that would take 10-20 times longer to do by hand in a basic graphics program can be accomplished much more efficiently using the built-in tools in a real graphics program) to illustrate what I mean. Er, see the attachment.
The dolphins still don't really suggest Minoan/Cretan/Atlantean to me. (If you don't want them to be any closer to that style, that's fine; it's your tileset, not mine!) The purple shadowing is an interesting idea, but in execution it reminds me too much of primitive, limited-colour-palette graphics, which I don't think is the look you're going for...? Also, is the crystal skull the small object between the small dolphins and the tridents? I was thinking of something large enough that the details (eye sockets, etc) would show up -- Knytts are quite small after all -- but I do like the direction you're going in with the eerie-glow-ish colours.