Hey, all.

I've started working on this again after a break. I'm trying to go for something slightly less ambitious, so that might make it easier to follow up on feedback more regularly.
The pines look slightly flat and washed out, maybe try to add/redistribute some highlighting to the branches closest to the viewer for more sense of volume?
I'm barely using the highlight color at all in those trees, so I'll try to bring out the center branches a bit more.
I think this gets to the heart of this issue in general, all of these assets are beautiful, but in a holistic sense are kind of of fighting for my attention. At least in the immediate background, further back then that looks very pleasant, but your inner most background is a bit distracting in terms of all of it's sharp detail & bright highlights . This may be less of an issue if you plan not to have character or object assets over the top, but it's something to consider it you wish to take this further.
Yeah, the over-detailing became obvious when I started adding sprites to the mix, something I should have done much sooner. I suppose the front layer assets could still be useful in a title screen or something similar where they don't have to compete with sprites for attention.
I made a quick and dirty edit to show some simple ways to tone down the details..
It's really hard though, because details look great when you look at them individually and instinctively you want to keep them.

But some more drastic measures might be required as it's still amazingly sharp in a lot of places.
Maybe tweaking the palette and saturation of the darker shades might help take some edge off?
That looks much better, especially with the more muted middle layer. I also think the darker rock tiles look nicer, but it was tricky getting the darker style to work when I started working on additional tiles.
maybe you could make the grass and leaves different tones? (like in autumn) That might help to break up visuals.
The grass and leaf ramps are separate now, which should help make the separation between platform and scenery more obvious.
Or you may just want to put the trees into the parallax layer, and have ledges as the platform layer.
I like this approach, mainly because it's simple, but I think creating a separate asset set for the foreground greenery will make it easier to reduce clutter.
will u be adding slopes and stuff?
I'm going to add 1:1 slopes next, yeah.

All right. The new tiles are 32 x 32 pixels, so one third of the size of the old ones. The main disadvantage is that they're much more repetitive and uniform, so I'll have to add more tiles of the same type for variation. I want to try to reintroduce some of those larger rock planes somehow, while keeping the tile count limited. That's going to be tricky, but editing the tiles will be a lot easier now.
As much as I liked the larger tiles, they were extremely tedious to create and iterate over. The initial set was going to be those three original tiles combined with three more. I darkened the bottom tiles by limiting myself to the darkest colors, but I found it difficult to achieve the same level of detail that way. They also were a little too dark compared to the rest of the assets, mainly because the tile size also resulted in really large platforms.
It also become much clearer just how simple the old grass was. I tried to squeeze in another grass color in the old tiles, so that I could swap the green ramp in the trees with the grass, but it turned out easier to start from scratch, as the platform parts of the old tiles weren't uniform enough and would have to be changed anyway.

Here's a mockup using an older version of the new tiles. I tried to reduce the contrast in the middle layer by darkening the highlights and brightening the shadows and also pushed the shadows more towards blue for stronger atmospheric perspective.
I've added some floating platforms, which means the assets are distributed more in the vertical direction, unlike in the old mockups. It looks a bit more game-like this way, I guess, but there's also no clear horizon anymore. Adding slopes might make it easier to achieve a more horizontal geography.

Here I've tried to reduce the clutter in the rocks a bit. I've been struggling with elimination of the grid while at the same time keeping some variation in the tiles.

Here's the current iteration of the player sprite. I've tried to make her dress look mushroom-like, something that resembles a mushroom cap in texture. I'm also trying to limit the color ramps for sprites more than for the tiles (which mainly use 4-color ramps) to make sprites cleaner and easier to animate.
What I'd like to do next is add a few more sprite elements and then try to add some more greenery to the front layer, but in a way that doesn't compete with the platform parts. Maybe greenery as platforms would work?