I'm a programmer. I've experience in Java, python, and c++. I see that some big games are built using game engines (Crysis uses Cryengine). However, other don't (Bayonetta for example). what's their approach ? Do they start coding from scratch using OpenGL or Directx ? is this approach feasible considering time, cost, porting to many platforms ?
I want to know what's the options before I start