* Take your time in the first few levels. You can make a high score
  by leaving one person and waiting for more people. 

* The last guy in the row will almost always leave a tip. If a person
  leaves the bar in the first level you get 50 points but, if you let
  them get close to the end of the bar, they will drink the beer and 
  stay. It's 100 for getting the empty mug. 

* The longer you stay in the level, the faster the people and mugs 
  move.

* Here's a Tapper Easter Egg. In the attract mode, wait until the 
  word Tapper is filling up with beer, and hold down the joystick,
  both taps, and the player 1 & 2 buttons. You will then see the 
  names of the game designers.