Not bad. It does give excellent and easy-to-follow, step-by-step instructions in how to tie the knots, but the explanations of what each knot is for are impossible to read before they disappear, which will leave a beginner in the lurch without knowing when each should best be used. This needs to be part of the existing user-controlled "how-to" sequence.
Downloading the majority of the knots is weird but isn't really such a big deal, but that section contains most of the most commonly used and useful knots, instead of putting them in the first section! Seems a bit backward to me.
It would be nice if they were alphabetized - but also if they could be sorted by most common/most frequently used, as well as easiest to hardest.
And as others have also mentioned, there's no square knot for some reason! This is *the* most basic useful knot there is, and arguably the most important. It's absolutely inconceivable to leave it out of any knot-tying reference. It's a very easy knot, but one which people often screw up.
The best use of Animated3DKnots as a result of all this is for those who already know when to use each knot but just need a refresher on how to execute it. A beginner will certainly also learn a great deal, but should also consult other references to find out when each knot is best used.