Quote Originally Posted by User137 View Post
Was it that some of OpenGL 2 and earlier commands don't even work on OpenGL ES?
Yes, that's right. Fixed-function pipeline don't work in OpenGL ES 2 along with some other deprecated functionality. This is why if you stick to core OpenGL 3, you get relatively clean API, which should be mostly exchangeable with OpenGL ES 2.

OpenGL ES 1.1 still has some legacy functions, but it is a deprecated API.