"Nintendo says they sold 500,000 copies [of Galaxy] in its first week, which makes for a great headline. But in my eyes, that's borderline failure," Comeau told TheStreet.com on Friday.

"It's an incredible disappointment," the analyst added, "when you consider that Halo 3 sold 3 million copies."

But even though Comeau thinks Galaxy has fallen short of commercial expectations, he can't say enough about the game's fun factor.

"I think Super Mario Galaxy is six times better than Halo 3," he said. "It's the best $50 I've spent this year on a video game."