HTML5 Game Development Tutorial
canvasdemos.com
canvasdemos.com
And yes, I know there's still a whole youtube/MP4 scene around demos, but I feel like there's something similar to the old spirit of "hacking pitiful 386 boxes in 100kb of space" when you're trying to do it in "a pitiful web browser element using a ridiculous programming language."
Not exactly my favorite language.
You forgot to mention that the memory issue is on the come back too ;p
Let's not forget the limiting factor of bandwidth which is also a big issue for a lot of games (texture loading).