Mega Man 2: Light Labs is the second Mega Man Metroidvania (series) game. It is a retelling of Mega Man 2.
The game has 16 distinct areas to explore. The first is Light Labs, which is where you start. Here you can heal, save, adjust difficulty levels, shop, etc. It also has a door to the teleporter room. The teleporter room can teleport you to all eight Robot Master levels. Like the first game, they all have small town areas at the beginning and a save station at the boss. After you defeat them all, the basement in Light Labs opens up which has more teleporters in it. You have to go through six different areas, one per teleporter, called Wily Stages. Upon completing the sixth wily stage, you have completed the game.