Is it for a platform game?
If it is then the gradient seems "off", I would rather use a dark shade below the rocks and the go single color downward. I would also try and "soften" the top of it.
If you upload it as a png I could show you how I mean.
1. Never use JPEGs for game screenshots
2. It doesn't look neutral enough to be tiled. Either add more detail (white dots) or lower it to a pace where it doesn't look tiled.
3. It's using gradients. Don't gradient.. color shading should follow lighting. Look at Knytt Stories; it's got excellent tiles.
Disclaimer: Any sarcasm in my posts will not be mentioned as that would ruin the purpose. It is assumed that the reader is intelligent enough to tell the difference between what is sarcasm and what is not.