Let me start off by saying this is an amazing art style and I wish to see a lot more of it.
Saw some of these pieces on PixelJoint (I think?) and I was certainly interested. Welcome to Pixelation!
So let me get this thread rolling since you deserve a lot of attention!
So a few things to try tie this piece together a bit more.
Forgive me if I explain anything you already know (or sound condescending, which is not my intention), but I'll go over everything I can think of in case you haven't thought of anything, or for the sake of anyone reading this hoping to learn.
When making games it's important to give attention to important areas of the screen.
Normally this means things the player can interact with get the highest preference. Examples of this are that the character is
the most important thing on the screen at any given time. All characters are. Then come things that you can directly interact with. Maybe you can ride the bike, go into the house, smash the flower pot. These things are the next important thing. Then there's impassable stuff that you can't actually do anything to, so trees, cliffs, rocks, etc. Finally comes background detail stuff that has no baring on the game whatsoever except to look pretty and give the eye something to do over the rest of the screen. Lowest priority of course.
There are several ways to attract attention from the player: contrast, saturation, detail and movement.
Since your game will not be having many colours, using saturation would be tricky, but do keep it in mind (means you'd have to set aside certain colours only for use on high priority objects).
Contrast is, on the other hand, pretty easy to use. Especially because this will often also lead to extra detail in a piece which will attract even further attention.
Movement is a way to make your characters stick out more without necessarily overcluttering the sprites, so make sure you have idle animations!
A note on your colours:
You seem to be entirely lacking in oranges (and thus also browns), which I was missing painfully while trying to make an edit, but it was too difficult to rearrange your pallet for just one extra colour. It should be noted that colour fidelity comes from the mid-range, so it wouldn't be impossible to just make one of your pinks orangey without affecting the rest of the mood, but it would require careful planning. Or you could just add some colours.
You are also lacking in really bright colours, but this shouldn't be a problem.
On to the edit for now.
So for this edit I wanted to only touch on a few things (for time reasons and because it's worthless throwing everything together in one go and it all being overwhelming). The dirt-grass barrier had
a lot of contrast going on for such an unimportant detail. So much that it was even distracting from your character. As stated above we don't want that, so I just dropped the contrast to deliver more attention to everything else.
The house also had too much contrast/detail on the roof which was making it the only thing the eye focused on in the scene. I removed some of the contrast, but you'll need to revisit the amount of detail you want on the roof for how much attention you want it to receive.
Oh and I edited that one rock, but looks like I've added unnecessary saturation to it, so it might even stick out more now, whoops! Reduced the contrast though at least.
It might be good practice to go over the piece and see what things you'd like attention to be given to and making some changes to get the desired effect.
I look forward to anything you come up with either way though, so please keep us posted!
[Edit] Added movement to the list of important things to attract attention with some explanation.
