Skulls of the Shogun may be the first XBLA game offering cross-platform play over Windows 8, Surface and WP8, but those hoping for a cross-platform purchase unlocking the game for all three devices at once, similar to Sony's PS3/PS Vita collaborations, will be disappointed to hear that it is unlikely to happen. 17-Bit's Jake Kazadal recently told Polygon:
"They [Microsoft] don't really have the pipeline in place to do it, but they're continuing to look into it. It's a little difficult because they don't support token stuff with mobile platforms. It might happen in the future, and if it does, we would definitely want to support that."
Skulls of the Shogun was set to release alongside Windows 8 back in November but was delayed due to the complexity of its multiplatform release. It is now expected to launch very soon.
Edit: The headline to this article has been altered for clarification, and a similar clarification helping to define "cross-platform" more specifically has been added to the first sentence of the article.