The giant cliff + elevator separating the two parts of the first stage was going to be a headache. I could tell trying to make it look nice and keep it optimized was going to be a pain in the ass. Originally, I also wanted this sort of transition from desert to forest, but trying to transition smoothly from two completely different color palettes was just going to be nearly impossible.
However, it's an idea I'm still considering. After removing the cliff, I think I can make it work.
Edit: and all that gray is just a blend texture I haven't blended yet. Most of it is going to be grass.