As a HUGE Kittyler (hello kitty fan), i surprisingly enjoyed this show! Sure, it doesn't have any other characters besides badtz maru and keroppi but what it does have is a fun concept that I could enjoy.
The inclusion of pinky and rio was actually surprising, as their only appearance was in the japanese show sanrio characters pon pon jump, i never thought we would hear about them again, ESPECIALLY outside of japan, i enjoyed the concept of kitty turning into different styles and the new characters and setting really add into hello kitty's world and add up to world building, i hope this show becomes more accessible in the future. The new characters are fun, frido is a highlight for many, but all of other characters that feel like they scratch an over-exaggerated Saturday morning cartoon itch that i have not felt in a while. My favorite out of the fresh cast is pinky, she's so funny and goofy, and vastus and zing having such a nice friendship is great. Also, something i like about this series is the expressions and lighting, it scratches an itch in my brain i never knew i had.
If you want a familiar hk experience, then this show is not for you, and even if i am a big fan of The Adventures of HK and Friends, this is a good fresh start on the hello kitty formula.