I've got progress. My game launches and achievements are working.
My current configuration:
Windows 10, C2 r209
Node Webkit v0.10.5
Greenworks 0.3.0
Steps that I've done:
1. exported game
2. updated package.nw (of course changed to .zip and after modification back to .nw)
2.1 added steam_api.dll - from link above
3. added steam_appid.txt to my games folder (with my game ID)
4. changed .exe name to nw.exe
But now the Steam screenshot (F12) isn't working.
What could be the cause of that?