I don't get why black-and-golden suit...
I live in russia all my life and I've never seen any uniform like that, but the flash is of high quality and is absurdly funny. I smiled :).
There's nothing I can call a cons at first sight, so I will just give it 10 because it's good.
Yeehaw!
I love it! Like you already said, it's a bit too much stuff happening in order to see and appreciate it all, but that's okay. It makes the whole thing kind of thrilling and fun to watch, since it's not just us sitting back and consuming but instead you actually have to look around the screen to see all the little details. I like it that way!
As to your questions: The mustache is fine the way it is, but I think additional sound effects are a delicate subject. Only if they're not too loud and don't appear too often.
Work Video
I haven't been this pumped before work ever! Zamechatel'no!
Kalinka
Kalinka, kalinka, kalinka my dear. Very nice.
Po Russky
Pribet...Cool animation well..nothing more to says