There's no way to discuss Castlevania: Judgment without at first acknowledging just how weird it is. In a series dominated by platformers (both harcore classic-style as well as Metroidvania explorational affairs), one not known for trying new genres far outside its wheelhouse, Judgment stands in a completely different genre, a one-on-one 3D fighting game, and it is quite an oddity.
Everything about Judgment seems anachronistic to the series as a whole. While featuring charactes from across the whole of the series (villains and heroes alike), each and every one of them has been drastically redesigned, given new costumes completely unlike what they wore in their previous games. Some characters play drastically different from their former incarnations, and others are given strange tweaks to their backstories to try and justify their inclusion in the game. It's hard to view Judgment as part of the series and not just some strange off-shoot gaiden game that exists in its own continuity. And yet, it's part of the official series.
From a different perspective it makes a bit more sense, though. Via it's own story, Judgment is about a compeition of the best heroes and villains, all drawn to together to fight for the right to take on Galamoth and the Time Reaper, two villains concerned with eliminating Dracula and remaking time as they see fit. Admittedly the story is a complete mess, but it does allow series director (at the time) Koji Igarashi a chance to take a victory lap through the series and have fun playing with all the "toys" he was able to create (and, for some reason, Cornell, who had previous been removed from continuity, so who the hell knows what's going on in this series anymore) And as a victory lap the game kind of works -- it allows us to have a grand mashup of all things Castlevania -- it's just a pity that it had to happen is such an awful game.
etting the weirdness of the story and style (everything we groused about above), Judgment just isn't very much fun to play. The core fighting mechanics are slipshod at best, and the whole package feels slapdash and poorly balanced. It's like Konami really liked the idea of a fighting game but had little knowledge of how to do it (which, come to think of it, they really don't).
So, in the end, what could have been a grand victory lap for the series (especially considering that not that long after this Igarashi would leave Konami for greener pastures) ends up just as a weird muddled mess. Thankfully the series would get one more try at a victory lap before rebooting all of continuity...