It is almost as if the developing team got lazy and decided to give up on the game towards the end
In Castlevania: Portrait of Ruin, you play as two young heroes: Jonathan Morris and Charlotte Aulin in the year 1944. The 2nd World War is occurring and has caused immeasurable amounts of suffering, anguish, and grief. Because of all this negativity that's been happening, many souls have become angry and evil which causes the legendary castle of Dracula to appear. It's up to the two heroes (one of them holding the legendary Vampire Killer whip in hand) to travel deep into the castle and find out how to destroy it, even if it means encountering the notorious Dracula himself. Things don't exactly go as planned though. It is shown that Jonathan doesn't even have full control over the Vampire Killer and even though they are indeed inside Dracula's castle, they do not find him there, but instead find another vampire known as Brauner scheming to take over the world. Even though the odds are against them, it's up to them to stop this vampire's plans by exploring the castle and destroying several portraits which house Brauner's dark power.
Like what I just mentioned, an interesting new aspect of this game is the fact that there are certain portraits stored away in Dracula's Castle. In order to make progress, it will be necessary for Jonathan and Charlotte to enter the portraits (each one containing a differently styled stage) and destroy the boss in each and every one of these levels to gain new abilities and weaken the vampire's dark powers. Unlike many of the previous Castlevania games in which your main goal was to simply find abilities to progress through the castle, eventually finding Dracula, this added goal was a nice way to try and avoid letting things get stale.
Another new feature which factors into the game is the whole "Dual Character" system which has you taking control of two characters simultaneously. Anytime during gameplay, you can switch simultaneously between Jonathan and Charlotte or you can even have them both on the screen at the same time (obviously with the AI taking control of the other character). Jonathan is pretty much like any other Castlevania hero out there, he relies on his weapons, tools, strength, agility, and flexibility to get him out of tight situations and defeat enemies. Meanwhile, Charlotte is on the opposite end as she isn't very versatile and definitely isn't physically strong but she makes up for it by being more focused around casting spells which will be necessary to get through the game. There are also some pretty cool combination attacks that the duo can use called "Dual Crushes" which are pretty strong and can be used to plow through normal enemies and deal considerable damage to bosses.
Other than those new features, when it comes to the basic control scheme and core gameplay, the normal fan of the series will feel right at home. Ever since "Symphony of the Night" was released for the Playstation, every Castlevania game has shifted from being a rather difficult 2D action platformer which has you relying more on your reflexes than anything else, to an RPG/Action hybrid which has a greater focus on exploration and finding new abilities. Castlevania: Portrait of Ruin is just like that as well. You'll find an array of new weapons, tools, and spells to use, and the castle is just littered with new platforming abilities for you to find so that you can traverse new areas.
While the gameplay seems pretty good right now with all the new features and core formula still intact, this game still suffers from some pretty major problems when it comes to one thing: execution. These new ideas which the developers tried to implement such as the dual character system feel extremely unpolished and honestly, not much of their potential is even used. Sure, you'll need Charlotte to open up certain places since she can cast spells and Jonathan can't but that's pretty much all she does most of the time: she casts spells. This means that for over approximately 80% of this game, you'll be using Jonathan since his flexibility, high strength, and constitution definitely makes him an ideal person to use as he can get out of tough situations with his continuous jumps and effective weapons. Meanwhile, if you decide to use Charlotte most of the time, expect to be hit by your opponent's attacks a lot and be prepared to have physical attacks with long recovery times (Jonathan's attacks are swift while Charlotte's book attacks take a bit longer). The dual character system also has a lot of other problems to it: there aren't even that many dual crushes to use which leads to you sometimes forgetting that you even have them, there aren't enough puzzles that make use of both characters, and so on.
Also, I don't know if the series is just getting stale for me or if it was just a poor design choice (I'm guessing it's the latter) but I found trudging through Dracula's Castle and the different portraits to be tedious and uninteresting. I could easily tell that it's because the level design was inexplicably dull. Here's one aspect of the game where it really felt that the developers got lazy: the graphics. Despite the fact that there are different sorts of environments to go through, the level design is so repetitive (you'll see similar hallways all the time) that before you even finish the portrait, you'll be tired of running through identical hallways with different enemies. This game's Dracula's Castle is also one of the worst I've seen, there aren't even any underwater areas or anything, there are just hallways, more hallways, a vertical shaft, more hallways, maybe an elevator here and there, and more dull hallways.
Don't get me wrong, I'm not saying that the level design is all bad. The "City of Haze" was a nice stage full of medieval European city details but even if there are certain portraits that are nice, some are very unlikable (like the "Sandy Grave") that after your first visit to these places, you'll never want to go back there again. I also can't help but mention the fact that the last 5 portraits of the game are simply recycled from the first 5, the level structure and feel is almost the same; it might just have different colors and harder enemies. Many enemy sprites are also recycled from previous Castlevania games. Honestly, it's like the team working on this game's graphical design just got lazy. This game unfortunately also made the same mistake as "Dawn of Sorrow" in which they took away the gothic portrait design for the characters and replaced them with cheap looking anime designs which definitely doesn't feel right. It is easily seen that this game is trying to aim for the whole "gothic" atmosphere with dark disturbing creatures and religious statues in the background, but whenever a scene happens and those cute anime faces pop up (together with the awful dialogue), it's hard to take this game seriously.
My views on this game's audio are quite different from my views on the game mechanics and graphics though. The game's music is pretty good, many of the tracks aren't really that memorable when compared to the music from other Castlevania games but it gets the job done. Yuzo Koshiro, composer for games like Streets of Rage and Etrian Oddysey, worked together with Michiru Yamane (one of the main composers of the Castlevania games in general) to create a large number of long and nice tracks for this game which mostly sound fitting. The sound effects also fit very well with everything that happens on screen and the characters and monsters are given English voice-overs which was a really nice touch. Unlike the graphics, it seems like there was actually effort put into this factor of the game and it definitely deserves some praise.
In terms of replayability and length, Castlevania: Portrait of Ruin lasts a good amount of time. I was able to finish the game in around 10 hours on my first playthrough (without getting a complete map and without doing all the quests) which is a good length for a portable title. There are also several bonus modes such as Boss Rush, Sound Tests, and alternate character playthroughs that can be unlocked after finishing the game which, if you are devoted to finishing them, can make the length of the game last to even 20 hours. All in all, this is the perfect length for a portable action game that is made to be played in short bursts. I do have a few mixed feelings regarding this like how the developers recycled basic portrait designs to artificially increase this game's length but that's only a minor complaint that doesn't have much impact on the length in the end.
Overall, I just found Castlevania: Portrait of Ruin to be an unpolished bag full of good and bad contents. The gameplay features never reached their full potential, the graphical design was incredibly repetitive, the dialogue is really bad to the point where its laughable, and the game just has an overall lack of polish which is evident through the numerous typos (Richiter Belmont…) and recycled portrait designs. However, by no means does this mean that Portrait of Ruin is a downright bad game. It still has the core gameplay mechanics that the Castlevania series has had ever since Symphony of the Night which pretty much guarantees some fun monster slaying and a certain degree of exploration, the music and audio in general also sounds very nice and suitable, and in the end, the game still has its good points. This game may not be that great when compared side-by-side to the other Castlevanias, but as an action platformer, it still does its job well to an extent. If you've already picked up the other 2 DS entries in the series and you still want more then by all means, pick this game up as well, but it's easily the weakest DS entry in the series so far and unless you can't find the other two or you see this for a really cheap price, I simply can't honestly say that I recommend it.