Ridley (Metroid)
Often considered one of the most memorable Nintendo villains, Ridley has been a mainstay of the series, having appeared (through various incarnations) in almost every "Metroid" game to date (all but "", "Metroid Prime Hunters" and ""). He has also appeared in the "Super Smash Bros." series, however, he had not been made a playable character until "Super Smash Bros. Ultimate" in 2018, making it also the first game overall to have Ridley as a playable character.
Metroid II: Return of Samus
"Metroid II" is an action-adventure game in which the player controls the protagonist Samus Aran on the fictional planet SR388. In this side-scroller, players advance through the game by using Samus' weapons to kill a fixed number of Metroid creatures. The player is given a detector that displays the number of Metroids remaining in the area. Once all the creatures are eliminated, an earthquake occurs and the planet's lava levels decrease, allowing Samus to travel deeper through its tunnels. The Metroid creatures are encountered in different evolution stages of their development cycle: original, Alpha, Gamma, Zeta and Omega. The more developed the organism is, the stronger its attack. "Metroid II" features save modules located around the planet, which allow players to save their progress and continue in another session.