I'll start by saying that anyone expecting a similar experience to the previous games will not be overly excited. The gameplay is great (and can be improved and most likely will be with free DLC updates, content etc), the narrative is decently strong for what the game is (given there is not much room for a strong narrative with how the game works in general), the length of the game is fine for the lower price tag (anyone expecting Skyrim hours of play is delusional lol), and the exploration associated with each area/level is fun.
A few gripes I have would be the lack of easter eggs, like for example when you are breaking garbage cans or similar items, you just get toilet paper and maybe food to heal, there are no little easter eggs of things you may have picked up, like a Faith+1 CD, or Cartmans coon mask.
The other issue for me would be the voice acting, and this stems from the most recent seasons/specials of South Park itself, there is a weird deeper tone to Cartmans voice that we've heard before but only when Trey has voiced him when notably sick, but in this game it's almost as if they didn't finish pitching Cartmans voice correctly and to me it just doesn't sound right.
Despite the flaws, and the insanely unfounded reviews (wherein they all just compare to previous South Park games), Snow Day is a fun one, and even better if you have friends to play with.