Multiplayer game as an extension?

I have seen that there are extensions that are games, but I am wondering if the game runs completely client side or if you can have the extension on the twitch viewers pc send and receive packets from a game server?
If anyone foresees any problems with this I would be happy to hear about it because I would make a regular browser game, but then I imagine I would get a lower conversion rate of viewers into players.
Also, can a twitch extension go full screen and accept all keyboard inputs besides escape or do extensions just use mouse input?
Thank you.

Extensions are just web pages, rendered as an iframe. The guidelines don’t allow for requiring viewers to download anything extra for the extension to work, but the broadcaster is allowed to download an external app for functionality.

If you want that iframe to communicate with a server then that’s entirely possible as long as it’s over SSL, and if it’s a game server you need the broadcaster to run then you’d likely want to run it through a proxy so that it doesn’t disclose the broadcasters IP to all viewers.

A Video Overlay extension can go fullscreen as it’s tied to the video player, so if you full screen the stream it’ll also fullscreen the Video Overlay extension. Keyboard shortcuts are not allowed, as it could interfere with the functionality of the Twitch player itself. You can use the keyboard for text input fields and things of that nature but shortcuts that provide functionality for the player always take precedent over your extension.

This is sad if there is no work around. In this thread:
It says: “When a viewer clicks into an extension, Twitch sends focus back to the player, to ensure that keyboard shortcuts for the player continue to work. However, if an extension asks viewers to click on a form field element (for example, “field,” “select,” “textarea”), and the viewer does so, the focus stays on the form element.” so I take it there are multiple forms of text input fields?
If there is a way that the user of the extension can click a text box, and have that text box submit their keypresses as they happen rather than when they press enter, then it would be possible to make a game that uses keyboard inputs until the time when the viewer clicks out of the text box with his mouse.
So it would be either mouse only or keyboard only. This is a very specific question so if no one knows then I’m still happy.
Thank you, Dist.