Update: Well, I've actually now got a working experimental PhotonPlayer multiplayer plugin for Construct 2. Here's a tantalising unfaked screenshot:
<img src="http://www.millercrawford.com/images-offsite/construct2/c2-photon.png" border="0" />
... and here's the C2 event sheet:
<img src="http://www.millercrawford.com/images-offsite/construct2/c2-photon-events.png" border="0" />
Yes, that's really all there is.
I've got quite a bit of tidying up to do over the coming week, before the code's fit for public viewing. After that, I plan on releasing it as an experimental plugin for playing around with and giving me feedback.
As you can see from the browsers screenshot, I have it running on localhost (WAMP server) - not yet the Photon Cloud, which was Taurian's original challenge.
Watch this space!