Sorry I'm late to reply to this.
I'll leave comments on your earliest levels and work backwards.



1) Your water seems a little too linear. Water doesn't behave it flows randomly within a defined space, however at certain points your water has carried on in the same direction for 5+ tiles.
I'm not going to lie, I'd rather put a straight line of water than it constantly changing directions, but you shall receive better resultsif you spend more time on the water.

2) Perhaps have less legs? I feel like having too many hinders the aesthetic capability in your level.

3) I'm not too sure on your type of shading but Shading allows Levellers to make a 2D level as 3D as possible. There's a few shading flaws in your levels, so I'll try to coherently address the matter here.
One thing I always tell people is imagine you are standing in the level. From your (The Graal player) perspective it would be 3D, so try and Level based on your Graalians perspective rather than what you see from your PC.

I'll show you what I mean.

Take this noob for example.
The way he's facing from his perspective he would see the back of a wall right?
Well since we can't see it, we use Shading to create that Impression.
The correct way which it would be implied would be through the shading on the right.


Try and use this concept a lot more in your levels to maintain the realism.
Hope this helps!

4) You're missing legs from your walk. Never leave them floating like that. It ruins the level

5) When you walk up stairs, Does the railing not go up with the stairs? Well in Graal, unless you can make the GFX for that you're tiles are going to have to go up as well.
Keep the Perspective.





6) Perhaps add more life to the Grass? Some flowers. Dirt patches under the trees. Make it wild (not too wild)

7) Your pathways need more life. Add a few Lamposts, Drainages etc.


All in all your levels are Improving each time. Well done