This seems interesting, but I feel like it would be way more useful if you could drag to rotate however you want, instead of waiting for the animation to get sort of close to the viewpoint you're interested in. It would also be good if the image wasn't covered by a big play button when paused - it's not really possible to pause it to look at things or adjust numbers.

I really like the visual representation of elementary row operations, but the intersection of the three planes is off their edges, so isn't actually shown. Also, "any vector multiplied by the three standard basis vectors in matrix form, i, j, k" uses a really complicated strange way to say "identity matrix" - you're not actually talking about multiplying by the standard basis vectors.

I found a bug (Chrome 65.0.3325.181, Windows): The scroll position is kept when you switch sections, so you have to manually scroll up to the top.