The multiplayer is a lot of fun, but Harmony of Despair could have benefited with a more accessible single player.
So Castlevania: Harmony of Despair (Or HD) is a first for Castlevania on a lot of fronts. First of all, it's the first side scrolling Castlevania title dedicated to the PS3 and Xbox 360. Secondly, it's the first in the series where multiplayer is the main focus. Given how popular multiplayer games have been this generation, there's little wonder why Konami wanted to bring one of it's oldest franchises into multiplayer territory.
In that sense, Harmony of Despair is a success. The game offers six player co-op online, and the PS3 version also includes four player local co-op support. The multiplayer functions quite well, and there's a good variety in the characters' play styles and all the items one can acquire in the game.
Harmony of Despair plays much like the games it was based off, almost to a fault. It's great to have access to a bunch of different characters over the course of the game's history. You can play as Alucard from Symphony of the Night, Shanoa from Order of Ecclesia, Soma from Dawn of Sorry, and several others over the course of the Castlevania lore. Each characters plays significantly different from one another, offering a good reason to run through the game with someone else. Each character also has his/her own items and collectibles, both of which continue to change the way the character's play style. For example, Shanoa can absorb enemy spells and then later equip herself with the same spell (like she does in Order of Ecclesia), varying the way you might take on foes with her. Jonathan Morris, however, can obtain various martial arts scrolls increasing his move set and making him more of a brawler.
Each character functions almost identically to how they do in their respective game. Each character's sprite looks like the game it came from, and the various moves, ability, and items are all named after the same game. It's great fan service, and get a bunch of Castlevania fans together and Harmony of Despair is great fun as you battle through familiar areas, fighting a large roster of great enemies.
However, this lack of an update can turn some gamers off. The Dracula X Chronicles was a great update of Rondo of Blood. The game was very similar, but it features 3D environments and more fluid animations, including a much more interesting look for Richter Belmont. If you play as Richter here, you play as his Symphony of the Night sprite, which is from 1997. Most of the enemies and environments are of similar aged material, but you can't help but wonder why Konami didn't go all out into making modern day looking graphics and trying to appeal to a new generation.
It boils down to Castlevania missing a demographic. Fans of the series often love the games, and Harmony of Despair's core gameplay holds up fine, it's quite excellent in fact, but the basis of the recent titles is gone. That is exploration and a single player aspect.
This is probably Harmony of Despair's biggest problem. You can play the game by yourself, but nothing changes from the multiplayer mode. While you play the game, there's a time limit in the upper right hand corner. It is 30 minutes in each stage, and during multiplayer this is more than an enough time to run around and gather various items and defeat the boss. However, during single play that limit can get irritating as enemies don't become any weaker. Bosses continue to soak damage as if there are multiple people fighting him, and it can be irritating. You can grind for rare items all day long, but taking on a boss one on one can be difficult, and not in the fun way, unless you have the absolute best equipment.
There also isn't a story. A lot of the characters are hundreds of years apart in Castlevania lore, but here they are fighting alongside each other. You can read somewhere that the story is about all the evil of Castlevania being written into this book, but luckily all the heroes are there too, but you won't find anything like that in the game.
It's just an odd idea. Ultimately, it works. Presenting a mix and match of Castlevania characters, stages, bosses, and music, while abandoning the single player and exploration aspect of earlier titles.