Of course, there should be very good and timely support, because often you can encounter various problems associated with deposits and other things, the user should not worry or spend his time on unnecessary proceedings, the user must play and spend his money.
This is somehow the same as the opinion I have, but for me, I consider animation and sound as what matters the most in an online casino. Why? Because for me the main reason why I play is entertainment, sound and graphics of the game impact the most to the excitement that we could experience while playing a game. In addition, of course the functionality of the casino should be in top to consider.
As what you've said animation and sound it important in online casinos. How about the speed of the website or platform? Does it really help your sound and animation?
Also the content and the colors used and the size of the text is what matters the most. Because most of the gamblers are old or 30 yrs old and above. So that range of age can possibly have a problem in eyesight. So be careful also with the combination of color, contrast and saturation that you will use in the online web or app.