[Johnny got his gun]

Main difference when working with Vexd's is that Engine uses entvars natives such as entity_set_vector where Vexd used Entvars_Set_Vector. You would need to rename all of those. There may be other stuff as well. You'll see when you compile.
I've remade several of my plugins for AMXX and there is no recoding needed, just rename a couple of natives.