Finally after some delays I could finish all the Game Boy Advance games of the Castlevania franchise. and now a quick and short review of them (which of course contains some minor spoilers too):
-Circle of the Moon: The most difficult of these Metroidvanias, but I liked the dark atmosphere of the graphic style, the varied enemy design, the power ups and bosses (probably my favorite final form of the count but didn't put it here as he doesn't get one in Aria of Sorrow). The only complains I have are the music, while I liked the "Vampire Killer" theme here, others just feel weak compared to other games they appear and the main characters...who are these guys, why Nathan uses the Vampire Killer whip? what happened to the Belmonts? since the game was declared non canon...we won't know
-Harmony of Dissonance: Most people consider this the worst for the music, the castle being just a lot of corridors and too easy. However I think the soundtrack gives it a claustrophobic feeling that fits the tone and also considering the castle was created by Maxine's memories (complemented with the "Simon skeletons") it's justified. As for the story I liked how while we don't get a explanation of Maxine and Juste's rivalry it's easy to guess where did that come from, how Dracula wasn't exactly resurrected here and Death is the main antagonist for the most part. It felt so fitting how it has the more traditional sub weapon system as the main character is Simon's grandson but added enough material to give it's own identity. My only complains were that the the decoration part was...weird, also it was kind of annoying how I was supposed to get the good ending, though no one complains about it so maybe it says more about me...next game.
-Aria of Sorrow: the one with most varied enemies, better (or at least more sinister) music and loved how Castlevania wasn't too big and the structure feel more real. though the story for some it may feel too anime (really Konami, entering Dracula's Castle through a Japanese shrine?) it's really interesting how it begins completely apart from the saga but later it gets more connected (even when fighting Julius the music had a lot of pieces of previous games' songs), and it's very interesting to see all the endings play out, and of course, you don't need to get 100% of all souls and areas of the castle, which gives a lot of replay value. The only complains I have is the shopkeeper, felt a bit out of place and the villain could have been more fleshed out. Still one that would include on a top 5 best gba games.