Mario Bros

Mario (or Luigi) must defeat all the enemies coming out of pipes in the corners of the screen. Enemies must first be hit from below to flip them over, then touched to kick them off the screen. However, if an enemy is left upside down for too long, it will flip back over becoming faster than before. Coins also come out of the pipes, and they give the player points.
Enemies in the game include:
Shellcreeper: A turtle-like enemy that simply walks around. They take one hit to flip. In Japan they are simply called turtles.
Sidestepper: Crab-like enemies that are slightly faster than Shellcreepers. They take two hits to flip. In Japan they are simply called crabs.
Fighter Fly: Fly-like enemies that hop around on platforms. They can only be hit from below when theyre touching the floor.
Slipice: A block of ice that slides around, until it stops on a random platform and freezes it. Most people today know it as a Freezie.
Additionally there is a small, square block labeled "POW" in each level. If a player hits this block from below, the screen shakes and all the enemies currently on the screen are flipped over.