The presentation is heavy on the assembly code side, and I felt explaining every indexing mode was perhaps a bit overkill, however after that was pretty good explanations of the incredible tricks used in the best games and demos to push the C64 way beyond what was originally thought possible.
This is what's so special about the Commodore 64. Any flaw is there to be exploited for benefit. One such example of this is the discovery that the SID chip 'clicks' when you change the volume register. Knowing this, you can rapidly rattle the volume register to manually control the speaker oscillation and thus create sampled sound rather than what the SID was designed for, synthesised sound.
As a gaming machine therefore, everything is fair game. Any flaw is equally a 'special effect'. The creativeness used by scene demos and game developers go way beyond what was even imaginable when the C64 first came out.
The Commodore 64 was also a successful productivity machine though! GEOS, the Graphical Environment Operating System for the Commodore 64 (that mimicked the Mac OS in just 64 KB of RAM and 1 MHz) was only briefly mentioned given the time limit and amount of content to cover, but if you would like an equally in-depth guide to GEOS I have written an article to fill in the blanks, including a 15 minute video demonstration, here.
Overall the presentation of "Everything about the Commodore 64" is pretty true, but this just scratches the surface. Every topic briefly mentioned extends into a whole wealth of information or massive community in its own right, if you care to dig further. Indeed as a primer to the quirkyness of the computer and the range of its capabilities this is a great presentation for those new to the hardware and those interested in knowing more since their days playing games on the C64 when they were kids.
I used a Commodore 64 exclusively from when I was 7 until I was 12, and then still daily until I was 16. I wrote my first IRQ screen split when I was 13, and coded a machine language interrupt driven mouse-handler soon after (for my own C64 graphical operating system). I learnt a lot from this presentation, especially about the techniques to smooth screen splits and opening the borders.
It's all the more exciting that these skills are still being passed on in 2008. The Commodore 64, despite being an 80's computer, is relevant today and I would highly recommend delving into it if you want to learn assembly programming.