Wani Wani World is a reskinned Berlin no Kabe released by Kaneko in 1992 exclusively on the Sega Mega Drive.
Charlie and Smiley, make their way through numerous screens of platforms and ladders filled with enemies. Their only method of attack is to bash a hole in the ground, wait for an enemy to fall into it, and then bash the enemy in the head, which causes the enemy to fall and transform into items and delicious food.