Format is very classic Nick with the slime hitting the ones who don't get the points. And the guy doing the robot host is pretty great at it. The part where they have the guy do awful cosplay of a character sucks.
There are indeed episodes with truly retarded kids. One kid gave an answer that wasn't one of the multiple choices. This is especially true during the question where they have to estimate things in a screenshot. You'll have a shot full of cupcakes and one kid will guess 4.
Despite being on the promo image, I don't think I've seen a single Hey Arnold question. Randomly you'll get one from Pig, Goat, Banana, Cricket or Breadwinners. Heavy focus on currently airing stuff. For some reason they count Dora as a Nicktoon and she's on there a lot.