Just think of Breakout rotated 90 degrees so that the bricks are at the right side of the screen and the paddle is on the left and you get the idea of Bachelor Party. In place of the paddle is a Spanish Fly, the ball is replaced by a sex-crazed male (aren't we all?) and the bricks are traded-in for two rows of females. You control the Spanish Fly and deflect the sex god over to the row of eager females, while preventing the man from getting past you. According to the manual, ever time the man has a dose of the Spanish Fly, he becomes energized and goes back for more good lovin'. As in Breakout, you clear the screen by doing the dirty deed with every woman on the screen. Yeow!
While I personally prefer the vertical screen layout of Breakout, Bachelor Party is nevertheless a decent clone and a hilarious one at that. Worth checking out if even just for laughs.