An astute blend of action, adventure, and RPG combine with Castlevania to produce one of the best platformers ever.
You play as Alucard, the son of Dracula as part of an effort to confront and destroy the Drac and all of his evilness. Shortly after the game begins, you are stripped of all weapons and armor and left to discover or earn your weaponry as you make progress. This game provides the opportunity to discover many secrets and gives you several points throughout the castle in which you can save your game. Additionally, each save points revives all of your HPs so that you can continue later without looking for ways to refill your life. Throughout the first half of the game, you venture through several different areas of the large castle in order to find and defeat the source of evil coming from the castle. If you find the right items and defeat the "final" boss of the first castle in a particular way, you can unlock an inverted castle, or upside down version of the castle you just beat. If you defeat the "final" boss of the regular castle without obtaining certain items first, you will technically beat the game by earning the "bad" (read: non-good) ending. Upon beating the inverted castle, however, you can unlock the "good" ending depending on the percentage of map you have uncovered.
The action and adventure in this game are first-rate, but the ability to upgrade and change armor & weaponry, RPG style, is a feature that makes the game truly appealing to many gamers. Throughout the quest, players will find many different swords, pieces of armor, headgear, and other items that they will be able to outfit the Alucard with in order to accommodate their preferences or defeat particular enemies. Additionally, players can find different creatures for Alucard to transform into (such as a wolf, bat, and mist/fog). The ability to transition into a bat is one that is not only essential to unlocking portions of the map, but was fun to use to simply roam around the castle at any time. Finally, players can use Richter, Maria, and even the armor of the Axe Armor enemy to play through the game once they have finished it. These characters are fun to use, but not necessarily needed to finish the game. They do, however, add replay value to the game and an element not present in many other games.
Overall, this game is absolutely worth playing and something that action and adventure fans should not miss. It provides players with plenty of action, adventure, secrets, and even multiple endings and is quite possibly the best game in a series full of great Castlevania games. You might be able to find a game you like better, but chances are you'll be hard pressed to find a better game.