New enemies are spawned at staggered points along the scrolling maps. To avoid getting overwhelmed by a full screen’s worth at one time, go slowly enough to spawn just one or two. Beat them up, then move along a little further.
Try this - it disposes of pretty much any of the non-boss enemies, although because it launches you quite a long way across the screen, you might not want to use it while facing right in a scrolling area. First, do the standard punch, punch, kick combo. Follow immediately with a grab, administer two knees to the groin, then vault over the enemy and slam him into the floor with a throw. Works every time.
The most damaging item in the game is the humble knife, even though it doesn’t have the ability to take down multiple thugs in the way the lead pipe does. Use it on the toughest enemies on the screen.
Sometimes enemies walk off the left side of the screen and refuse to come back to take their medicine. When this happens, wait a little way away from them with your back turned. Doing this at any time will also attract cowardly punks from anywhere behind you. Turn around and thump them when they get within range.