This is pretty much it, and if you are co publishing on other platforms the XBLA version NEEDS to have some exclusive content
Blame Sony for not stepping their game up enough to combat XBLA
My understanding was that it went like this:
If it's being published on XBLA, it has to be published concurrently, first (as a timed exclusive--which doesn't really bother me at all, since I tend to prefer XBLA-style games on my 360), or not at all (see a lot of same-day XBLA games).
If it's being published on PSN, it has to come concurrently, first, or have exclusive content. I personally find this far worse, and hate it when multiplayer games have system-exclusive content.
Since Microsoft is the publisher, I imagine that this, like ilomilo or Trials, will come to the PC when Windows 8 has their Windows 8 app store deal, but not before.
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This is the best 2D stealth game I've ever played. I'm already thinking about how I'll do things differently in future playthroughs. Thief, of course, is still the best stealth game ever, but hey, that's a fully 3D immersive sim. Kinda hard for a 2D arcade game to live up to that. For me, Mark of the Ninja is a solid 9/10. I don't really get 'combat' though. I'd like to at least be able to fight dudes if I make a mistake, rather than try to escape, run the risk of death, and start over.