Is there any particular look or mood you're going for with the colours?
Could you also post a 1x zoomed version, perhaps without the lighting effects? That would make it easier for people to make edits.
As a general rule, important/gameplay elements = more contrast, unimportant/background elements = less contrast. Value, hue, and saturation differences all create contrast, so for important elements, you'll want to vary all of those more than for unimportant ones.
The background and character are both dominated by midtones and both cover a full range of values, so the character doesn't stand out well. The walkable surface of the bricks/rocks is also barely distinct from the background, and could use more contrast. The highlights on the giant sword are very high-contrast and distract from the character and walkable areas. If the sword is not a gameplay element, consider making the it more of a silhouette with subtler details so that it doesn't distract. That might also help it read more clearly - I stuggled to see that it was a sword because I kept reading the highlight as an independent object rather than as part of the sword. With anything worth looking at, make sure the silhouette reads clearly.
The grass is quite yellow and looks lit by a late afternoon sun, but the rest of the scene is very blue, so the grass doesn't feel like it quite belongs.
The hue-shifting is inconsistent. The bush seems to get warmer while the grass gets cooler, and the ground stays largely the same hue. I recommend choosing colours for your key light (your main light source) and for ambient light(s) that work well together, such as complementary colours. Shift your highlights towards the hue of the key light, and your shadows towards the hue of the ambient light. This will help everything look like it's part of the same world, since it'll appear to be lit by the same light sources. It'll also help unify the palette in general, since there will be no ramps that are disconnected from the rest, and any "unfitting" hues will end up mixed with fitting hues, which will make them less prominent.
Lastly, more of a hack than proper feedback: Don't use white lighting effects, always give them some colour. White effects convey no mood and tend to wash out the underlying colours, making even beautiful palettes look bland. Your light effects should have colours corresponding to your hue-shifting of lights and shadows, since they represent the same lighting that give your scene its colours/hue-shifting.
