"has" vs "have" usage after enumerating two subjects, the first one in plural

Question

Possible Duplicate:
Singular or plural following a list

I'm inclined towards the 2nd sentence, because 1) the first subject is plural and 2) there are two subjects.

Sub-question: but what if the first subject would have been singular?

Specifications and game design has already been completed for it.

or

Specifications and game design have already been completed for it.

Answer 1

The verb should be plural:

The dog and the cat was were sleeping peacefully.

The specifications and design has have already been completed.