Valve's attempts to sell the wit-driven puzzle effort Portal separately through the online Xbox Live Arcade were shot down by Microsoft, the studio has revealed.

Valve marketing director Doug Lombardi said that the critically acclaimed title—awarded 2007 Game of the Year by the Shacknews staff and our readers—was held up by restrictions such as Xbox Live's recently increased 150 megabyte file size limit.

"We'd love to do that. Right now it's something we'd love to do. I'd love to sell Portal on Xbox Live," Lombardi told GamesIndustry. "[But] the platform holders aren't doing that right now. There's a size limit and all kinds of other things.

"We've asked them, we said we were open to it. So it's a decision for the platform holder and how they want to make the games available and how much bandwidth they want to [allow]," he added.

Despite the rejection, Lombardi noted that a downloadable Portal on consoles may yet be possible.

"I think it's a trade-off, we'll see it one day," the developer said. "It always happens once it's been proven and I think it's been proven now on Steam, so I'm sure it'll migrate back to the consoles just like everything else does."

Portal is currently available as part of Valve's mega-compilation The Orange Box (PC, PS3, X360), and available as a standalone PC title both in retail outlets and on Steam.