Classic is defined as "of the first or highest quality, class, or rank", and Castlevania: Symphony of the Night (SoTN) fits that description to the T.
SoTN is a port of the original PS1 game but you really wouldn't know it. Its 2D graphics are still very sharp and nothing is lost in the translation. You get to play as Alucard, Dracula's son, who has reawakened after a long slumber. He is trying to find out who has brought Castlevania back to life and vows to destroy the evil once and for all. The game play is typical Castlevania fare; find Dracula's parts, put them together, destroy Dracula. However, it’s the journey that makes it so much fun. Castlevania is no longer just a level-by-level place, it's open-ended and you can travel wherever you need to. There is a vast array of places to go including underground, a chapel, and tower. Alucard has the ability to change into a cloud, wolf, or bat allowing you to utilize those forms to explore. Alucard also has the ability to use magic and collect "familiars", which are 5 different objects or creatures that follow you with different skills such as attacking or finding secret passages. There are some RPG elements thrown in for good measure, examples including being able to change weapons, armor, and accessories.
As stated earlier the graphics are very good for a game from 1997 and the music is absolutely perfect for the game. It is both haunting and beautiful. Leaderboards and 12 pretty tough achievements have been included for the Xbox Live version but they had to cut the full motion video cut scenes. This brings us to perhaps the only fault of the game, the dialog and voice-acting. It is pretty bad although I believe that is the point. Its possible the developers wanted that cheesy action movie type dialog in the game. It is very annoying but luckily you don't hear much of it.
SoTN is 800 points ($10) on Live but would be one of the best investments you've made from Arcade. It is a lengthy game with lots of action, huge boss battles, great music, and solid graphics. This is a true classic of video games and should not be missed.