I am currently working on my desert levels and they are coming along nicely. Although, when I play through them, I don't actually feel like I'm in a desert/dry type biosphere.
I removed the clouds, changed the background music, started using bees/scorpions for enemies and added a few cacti and a pyramid. This helped a bit but I am still not feeling it. Actually, seeing everything I have done in writing makes me want to say its good enough, haha. But anyway, do you have any other ideas for what I might add to the background or foreground or other enemy types I could use?