I... absolutely am at a loss, I'm sorry. One way or another, there has to be something else on your machine that's conflicting with this, presuming you did a verification of the local steam files and it worked. Right now you're the only report of this not working that wasn't resolvable with some sort of general compatibility-with-unity-and-other-plugins thing that we found via google-fu, and I'm not really sure what to think about that.
Maybe it's a permissions issue; you should definitely make sure that you have full permissions to the folder that the game is in. I'm really reaching there, though. Beyond that all I can think of are things that hook into unity, virus software, and so on. You might get some mileage from specific command line arguments:
http://docs.unity3d.com/Manual/CommandLineArguments.htmlMost specifically:
-adapter N (Windows only) Allows the game to run full-screen on another display. The N maps to a Direct3D display adaptor. In most cases there is a one-to-one relationship between adapters and video cards. On cards that support multi-head (they can drive multiple monitors from a single card) each “head” may be its own adapter.
-- From Chris: This would help if it's trying to launch on some strange display for some reason, if you have one that's sometimes hooked up but not now, for instance.-force-d3d9 (Windows only) Make the game use Direct3D 9 for rendering. Normally the graphics API depends on player settings (typically defaults to D3D11).
-- From Chris: This would help if it's trying to launch via opengl or something for some reason, and failing for some strange reason.-force-d3d9-ref (Windows only) Make the game run using Direct3D’s “Reference” software renderer. The
DirectX SDK has to be installed for this to work. This is mostly useful for building automated test suites, where you want to ensure rendering is exactly the same no matter what graphics card is being used.
-- From Chris: this seems like overkill to me, but could work.-force-d3d11 (Windows only) Make the game use Direct3D 11 for rendering.
-- From Chris: I'm not even sure if this will work, because we have this set up for DX9 only. But you might be able to get some interesting results with this, I don't know. Maybe DX9 is messed up on your machine somehow.-force-glcore (Windows only) Make the editor use OpenGL core profile for rendering. The editor tries to use on the best OpenGL version available and all OpenGL extensions exposed by the OpenGL drivers. If the platform isn’t supported, Direct3D is used.
-- From Chris: This also gets into odd territory, but would use opengl instead of directx. On windows this probably means worse performance, although it's what we use on osx and linux. It's worth a shot, though.-force-glcoreXY (Windows only) Similar to -force-glcore but request a specific OpenGL context version. Accepted values for XY: 32, 33, 40, 41, 42, 43, 44 or 45.
-- From Chris: I can't imagine you'd want to do this, but who knows.-force-clamped (Windows only) Used together with -force-glcoreXY, but it prevents checking for additional OpenGL extensions allowing to run between platforms with the same code paths
-- From Chris: I honestly am not even sure what this is.-screen-fullscreen Overrides the default fullscreen state. This must be 0 or 1.
-- From Chris: This MIGHT help in terms of forcing windowed mode.Those are all the ones that I can see that really seem like they would be useful, although a lot of those are really a stretch. I hope one of them helps!