He came in today quite perturbed by my mocking, until I pointed out that's his fault for sticking his nose into something and taking it at face value. He did eventually see the funny side of it, after being caught hook, line and sinker.
Also: in my opinion, Mario Kart Double Dash!! is good. But only good. I played it, but I really couldn't warrant spending £40 on it, not after the gorgeousness of F-Zero.