The current Win32 version of NW.js or Electron is already over 100MB when expanded(or near 50MB compressed).
So I want to find a smaller runtime for personal use, as I didn't compile NW.js myself yet.
Tried many node-webkit runtimes from many existing HTML5 games, the NW runtime from RPG Maker MV(which is publically available) works better, adopted some customization and made sure it works with Superpowers, this is the binary:
The runtime is 25MB zipped, somehow acceptable size, however it seems to be a relatively old version of Chrome inside.
Personally I don't encourage you to use "Unknown Binaries", but this one was personally tested by me and VirusTotal, if you have time you can get Node-Webkit(now NW.js) or Electron and package yourself.
BTW, there may be some compatibility problem that I didn't found during test.
The next step is to build a compact one myself once I figured out how to build NW.js properly.