Here are the two most important pieces of information you could possibly receive if you're planning on picking up Castlevania: The Dracula X Chronicles:
Play through the game to level 3' (you can do so by dropping into the first hole you find on level 2 and progressing through the level to fight the alternate boss.) In level 3', head through the level (heading up all stairs) until you find a skeletal snake. Kill it and destroy the hanging plant nearby, probably by using a subweapon, and then jump on the new platform to traverse the section on the upper level. When you get to the end, you should find a tombstone that contains an item which will unlock Symphony of the Night.
Play through the game to level 4. Progress through the level (heading up all stairs) until you reach a section with six skulls in a tower. Destroy them, and when you reach the wall further on, destroy it to find a bomb. Set it off with a whip-crack and do a bit of platforming in the revealed section to get to the upper level. When you get to the end, you should find a candle that contains an item which will unlock the original version of Rondo of Blood.
Voila! You've now unlocked the two thirds of the game that the developers have seen fit to hide in an unnecessary and obscure fashion! Huzzah!
God, Grant Me Strength
Now that unpleasantness is out of the way, time for the actual introduction to the review.
As the prequel to Symphony of the Night never released outside of Japan, Rondo of Blood has gained a near-mythical status, particularly as it was released on a system that was never very popular outside of Japan anyway (the PC Engine) and then received an incredibly inferior port to the Super Nintendo that was released internationally.
Well, series führer Koji Igarashii (who was only nominally involved in the creation of the original) decided to update and port the title to PSP, and Castlevania: The Dracula X Chronicles is the result: a 2.5D remake of Castlevania's "holy grail" that includes the PC Engine original and Symphony of the Night as (gnngh) unlockables.
An Evil Prayer Summons Darkness
I'll be completely honest. As a big fan of the Castlevania series, I've played through the PC Engine original, and while in many fans eyes it's the perfect fusion of the brutal, old-school NES Castlevania titles and the Metroid-esque direction "IGA" has taken the franchise, I think that's a load of old twaddle. Main character Richter Belmont is as limited as Simon Belmont, crawling along like he's cacked his pants and completely unable to react swiftly to anything (his one special move, the backflip, is practically useless) and the game is simply too rigid in its rote-learning based design to be rewarding at all, especially when it comes to the punishingly hard bosses.
If there's one saving grace to the original title, it's the ability to unlock Maria, a second playable character who, by virtue of her quick attack and double jump, makes the game bearable enough that you might actually enjoy discovering the innovative aspects of the title, such as alternate routes through the levels.
A Nightmare Reborn
Although some changes have been made for the remake, such as new sections and a ludicrously tough third form for Dracula, for the most part the Dracula X Chronicles is the same game as Rondo of Blood, right down to requirements including pixel-perfect jumps (much harder in 3D, especially when they usually require that your character be hanging off the edge of platforms to be able to reach the next) and frustratingly difficult set-pieces. This is the kind of game that will happily drop you down a bottomless pit (and lose you a life) if you forget to hold a diagonal when walking up or down some stairs. God only knows how unbearable that is on a fat PSP.
There's something oddly compelling about the complete package, however. The remake features some great new art (from Symphony of the Night character designer Ayami Kojima) there's always the original PC Engine version if you really don't like it, and the version of Symphony of the Night that's included is the best available, with re-written and recorded dialogue (so no "a miserable pile of secrets!" for better or worse) extra familiars and even the ability to play as Maria. For completionists, it's far better than the downloadable version available at the PlayStation Store.
You can even play through any of the games with Japanese or English voices. Now that's attention to detail.
This is really a release made for, and by, Castlevania fans. If you don't think much of the series, this isn't going to change your mind. I wouldn't think much of it either if it only included the remake, but the tip-top ports of the original Rondo of Blood and Symphony of the Night bump the score up a couple of marks easily.