Take in account Mali-400 does not support high precision floating point number in fragment shader. So if you have some device with Mali-400 or you want full compatibility with this GPUs, you can not use default depth shader. But its easy rewrite them (my rewritten shader is little bit faster). If you want, I can share them. And if you want some numbers, one per-pixel point light, one per-pixel spot light, post-processing image effects (distortion), one rendering of depth buffer, one rendering of motion vectors and motion blur effect (4 samples)... game is running 49fps on Samsung Galaxy S3, without motion blur (and everything needed for this effect) it is 60fps. So your app can running smooth with shadows too. But take in account, these numbers come from high-end phone.