Optimize Game on iOs

Hello my name is Yar and I am developer behind game www.molecats.com.
Currently I work on port our game on iPad but I have problems with performance.
Our game using a lot per pixel shaders, 3d meshes.
So I switch to use baked Lightmaps but we still have low fps.
We tried remove light, switch all shaders to Mobile/VertexLit, etc. But only switch to VertexLit Render giving some boost in fps on Retina and I am wonder if problem in old iPad Air or in something else. I am think that there a some gpu bottleneck problem but can't find.

So I looking for any help/suggestions how I can improve performance.

Thank you.

 

Using built in terrain? Using a terrain shader with blending? Using any water shader? I'd recommend profiling in editor and on device for hints about what causes it.

 

we using mostly alpha+cutout, but the main problem when we switch to plain Mobile/VertexLit still have low fps below 30fps

 

I am looking into overdraw, but after remove many meshes and clean up scene, we still have issues.

I can prepare ipa for test.