Particularly the Poopsies and Dr. Hawkins' visit to the, er, the M Karzi. There were a few times that I reloaded a game just to hear a sound effect or a little line of dialogue. This is an amazing feat. Most games can and should be played with the sound off, but MDK2 is not one of them. Yes, I am.
Control is beautiful.
I would also rebind the keys immediately. The thing to remember is that all three characters in the game have a separate set of special controls, so set those up as well. The mouse gives you fluid control over the characters' facing and the WSAD keybinding is a default option.