Please don't use the "width" parameter when posting images, just use plain [img]. The fixed width prevents zooming, which makes it harder to look at your image and give you more detailed feedback. The "img width" feature is meant for clickable banners and such, not for sharing art for critique.
MysteryMeat is right, avoid having highlights everywhere. Use them to draw the viewer's attention to important things, such as the parts of the environment that the player can interact with directly (e.g. the tops of platforms).
The edges of your tiles are perfectly smooth, which makes all your hard work on the textures in the interiors of the tiles feel a bit wasted. The edges should be as textured as the interior, since they're the same material.
The edge tiles are distinct from the interior tiles, which means they're an opportunity to create variation and a more natural look. By copy+pasting substantial portions of different tiles, you're squandering that opportunity and making things look more copy+pasted than they need to. That's fine for tilesets that have cartoony textures or that are meant to depict repeating textures, but you seem to be going for something more natural-looking, something that should have its repetition minimised.