This reminds me of a method of trying to evaluate art in an objective way. Basically you ask yourself 3 questions:
What is this trying to do?
Does it succeed in what it’s trying to do?
Is what it’s trying to do worth doing?
If the answers to 2 and 3 are “yes”, then it’s probably a good work of art. This helps remove the subjectivity of “do I enjoy it?” when evaluating a work.
I would say the answers for Desert Bus indicate that it is indeed a good work of art. It succeeds in being a monotonous parody of a video game which makes a political statement about what games would be if they lacked any fictional elements or conflict. And I think the statement P&T were trying to make with this game was definitely worth making. Plus, we know from the amount of people who play it as a streamed challenge game that there is some desire for a game like that to exist.