These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Accidental Innuendo: All over the place. Especially from Tita, which might not be so accidental.
Angst? What Angst?: Castlevania is dripping with it, but Kokoro is pretty cheerful and upbeat.
And that's also in spite of her possible big brother, Julius, disappearing from her life before she was even at elementary school age, and she won't even know he survived until she's about forty. Geez.
Anti-Climax Boss: Compared to her previous forms, Dark Force's final form is quite easy to fight.
Broken Base: Many non-Japanese fans of Konami's previous Shoot Em Ups have a cold reception towards the series. The complaints usually aren't about the gameplay, but the amount of Gag Boobs, Fanservice, and Stripperific characters. Some do have complaints about its grind-heavy but otherwise very basic Gradius gameplay to the point of considering other cute'em ups superior in this regard.
Following tradition, the sequel has a total of eleven soundtracks to choose from, with many notable tracks that appeal to nearly every musical taste, from orchestra to techno to rock and roll. Nearly 30 musicians from all over the world did work on Otomedius Excellent's soundtrack.
It's generally felt that Kokoro Belmont's soundtrack is a a subversion, ergo, Crowning Music of Suck. It was bad enough that a pair of industrious Internet Heroes set out to fix it.
Cult Classic: Getsu Fuuma Den was... obscure, and yet gets a prominant reference in Otomedius in the form of Gesshi Hanafuuma.
Ear Worm: Aircraft Carrier is in this game, too. Twice. And just like every other game this theme appears in, it gets in your brain and refuses to leave.
Many of the D-Burst attacks can make very short work of most bosses.
Esmeralda's Pulse Laser is unintentionally, ludicrously overpowered. It ignores the damage caps obeyed by all other weapons in the game. Placing an Option inside a boss (easily done with Esmeralda's Whip options) and holding autofire will, essentially, cause the boss to die instantly.
In Gorgeous, Gravity Bullet (as used by Poini) was quite broken. In Excellent, it's even nastier.
Moe: Poini's said to be the lovable little sister of the entire squadron.
Every major US reviewer panned Excellent quite harshly, in ways that are commonly taken to reveal none of the reviewers even liked Shoot 'em Up games and have no business reviewing one.
Other reviewers gave the game harsh treatment despite clearly never even playing it. For instance, Destructoid's review of the game uses only the promotional artwork and screenshots to base the entire review on, and did it in an extremely offensive way to boot.
This extends to the actual fanbase as well, as noted in Broken Base.
Scrappy Mechanic: To get new weapons added to a character's selection, you need to either make money or hope to unlock the weapon card for the first and second game respectively. This effectively forces numerous replays just to get a decent selection. The second game is better about it as weapon cards apply to all characters that can use them compared to the first game where you had to grind for each character. This is often a point of complaint in fan written reviews and articles.
Values Dissonance: The name "Poini Coon" is clearly because she's meant to resemble a raccoon, much like Diol looks like a catgirl. However, her last name was changed to "Kune" in the English release as "coon" is a racial slur that the developers likely hadn't been aware of.