Great thread idea!

One of the biggest things that LoS did right for me, was engage me in a way no CV game has since Dracula X Chronicles. I've put more hours into LoS than I have in a non-fighting game in a long time. I've beaten the main game on all the hardest difficulties, finished the Trials, gotten all the items, and have only the DLC stuff to finish. The game is FUN!
-The Combat system is excellent. Most moves easily chain into others making it easy and fun to come up with your own combos. There's a couple really fantastic LoS combo vids on YouTube that really show off the engine's potential.
-The platforming and "shimmying" were great, albeit not as challenging as I would have expected. It reminded me of parts of CV64 where you're climbing on the outsides of structures to get around and making jumps that make your palms sweat just anticipating it.
-The atmosphere of the game post-Agharta is stellar. The dark, moody, and in some cases plain depressing locales especially Veros Woods, the Castle Hall, the Clock Tower, etc totally make me think of Castlevania 4's dilapidated levels. The levels, for the most part are well designed and make sense for what they're supposed to be. And there are some cool ideas for levels too like the Music Box and the Titan Graveyard (I know a lot of people didn't like it, but I thought it was cool strolling through a wasteland of dead titans.) But even the levels that weren't as dark like the Dead Bog were still beautiful to look at (especially on the PC version) and interesting to traverse.
-Gabriel is a bit how I imagine Simon might be if he had dialogue. In a way, Gabriel is the essence of a Classicvania Belmont, maybe a little more brutish, but still real no nonsense in a "my-neck-is-on-the-line" kind of way.
-There were some really cool enemies. The game's take on the vampires was interesting especially, and I liked the werewolves. I hated the titan fights, but the Dracolitch was really cool fight and extremely well done. In fact, a lot of the boss fights in the game were great. I wish they'd seen fit to have a Boss Rush mode in this one.
-Above all, LoS built on the shoulders of previous CV games (largely the 3d ones) in a cool way while bringing something new to the table.