Like the sphere effects in other engines like construct 3 or clickteam fusion, why wouldn’t this engine be capable of implementing this feature. I really hope in the future this will be in the engine. 
If you wait fake 3d at short term in GDevelop, you should use a another software.
Or see what the community have made.
Try the layer effect “Displacement” - Layer Effects [GDevelop wiki]
Maybe if you apply a radial gradient it can distort the screen the way you need it.
Unfortunately not, the effect seems applied from 0;0