vcbuild.bat creates a Release/iojs.lib, but node-gyp (including the one bundled with io.js) looks only for a Release/node.lib.
My node-gyp build blew up with a LINK : fatal error LNK1181: cannot open input file 'C:\opt\NodeModules\io.js\Release\node.lib' [C:\[...]\hello-world-native\build\binding.vcxproj]
until I copied Release/iojs.lib to Release/node.lib.