Another classic series by Konami that originates on the NES.
In the early Castlevania games you're playing as the whip swinging, demon slaying Simon Belmond.
As you towards the end of the stage you fight monsters not by shooting or jumping on them, but by hitting them with your whip.
Unlocks are found in torches spread throughout the stages.
The main difference between Castlevania and other games from its time you'll notice is the setting.
Unlike in games like Mario or Contra (Probotector in Europe) you won't find yourself walking through colorful mushroom worlds or futuristic cities, but rather old, european castles and forests with a creepy atmosphere.
The music is once again excellent.
Everyone should try a Castlevania game once, 'cause this ain't your run of the mill jump and run.
If you've never played a Castlevania game I'd recommend to start with one of these (in that order)
1) Castlevania (NES)
2) Super Castlevania IV (SNES)
3) Castlevania 3 - Dracula's Curse (NES)