darceyo Have you seen our demos and examples in spine-runtimes/spine-ts/spine-webgl? You should be able to get the basic code from there: spine-runtimes/spine-ts/spine-webgl
If you still have any questions after examining them, please create a new post to ask the questions.
As per the documentation, you have to install NodeJS and then run npm run dev for those files to be generated.
Please read the documentation. These are "web version" examples. They use our spine-ts runtime and backends, like spine-webgl, spine-canvas, etc. However, for the "web version" examples to work, the code of the runtimes needs to be compiled to .js files, like the spine-webgl.js file your browser complains about. For that compilation to happen, you need to compile them, which is done via npm run dev.
You can also use spine-webgl by linking the unpkg.com files. Either way you'll need to read the documentation.
That said, the easiest way to show two animations side is the Spine Web Player:
http://esotericsoftware.com/spine-player
Nate the easiest way to show two animations side is the Spine Web Player:
http://esotericsoftware.com/spine-player
Seems that you are making great progress! 
For some weird reason, I tried googling Spine Runtime for C2 today and saw this in the result.
I got excited for a minute there that finally, I see an update about a runtime for C2 after all this years!
It's understandable that a runtime for C2 will not be pursued. But it's still sad.
I also prefer C2 than C3.
I'm still hopeful that maybe one day will come and someone will make one. crosses fingers
