This might not have been possible with CoffeeScript, but for your next project have you considered targeting both the web platform as well as native using a language that supports both? 
As far as I can see the main benefit of targeting HTML5 is the accessibility, especially for this demo. It would however be nice to get a native version for Steam (and possibly mobile platforms if those are on the horizon too). I think using Unity will get rid of this benefit as it will require the Unity plugin to be installed to be playable.
1 - A good example of a game that does this is Reel Valley, a game built to be played primarily on Facebook's game platform in the browser, but also targeting Android and iOS. Its code base is shared across all platforms with only small platform-specific bits needed for each. Definitely worth checking out: https://yglukhov.github.io/Making-ReelValley-Overview/.
As far as I'm aware the Unity plugin is dead and hasn't been pretty much disfunctional for over a year now. The new approach for Unity is to export directly to HTML5, which already works somewhat nicely. Of course you have to pay with big package sizes since you're bundling the engine with your game. That's the biggest advantage of using a custom HTML5 engine which is custom tailored for one game.
We've been selling the web version before the steam version, but after putting it on steam our revenue exploded 50 times and we put the web build a bit on the back burner. We're coming back to it now and will experiment with some ideas benefiting of the immediacy of the web tech. Even thinking about doing a MMO-ish web-only spin off for it.
Will check out the ReelVally blog post. Very interesting.