[kenjackson]

If the candidate uses up all of the interview time trying to obtain perfect requirements, we have a problem

I don't know how long your interview is, but if its just an hour and if the game is as ambiguous as you seem to say it is, I think its the fault of the interviewer, not the interviewee. The interviewee doesn't know what your schedule is -- unless you tell them, "You must code monopoly by the end of this hour, warts and all". But otherwise, I think its reasonable to take the full hour on requirements. In real life, an hour on requirements doesn't describe if there should be a splash screen or not.