So far I've beaten the first two "parts" of the game. Gameplay spoilers below for people who want to find out how things run this time around on their own.....
This reminds me a lot of Mario 64. Listen! There's the castle (with amazing music, btw), and within the castle are paintings that you go into that are of different levels. I've gone through the town portrait and the pyramid portrait so far. It's SotN-style gameplay in new locales, which is AWESOME. It's better than, oh, here's the Castlevania lab, here's the Castlevania garden, etc. It's very familiar (some enemies WILL NOT GO AWAY EVER, right Skeleton Archer?) but it's fresh at the same time.
The puzzles are cool. For example, you get this wonky double jump where you need your partner on the screen and you jump off of his/her shoulders. Way cool. Then you get another normal double jump later on. Cooler. But jumping off of your partner's shoulders and then double jumping even higher to get sweet items and shit? The coolest. There are other commands, like telling your partner to stay where he/she is standing. There was one puzzle pre-double jump that made you hop on top of a pillar, then command your partner to stay. You have to jump down, push the pillar across the level, and then switch your control to the partner on the pillar so you can progress. It's really great.
The pyramid boss was tough as nails until I realized that I had a bomb special ability called 1,000 Knives (or something like that), kind of like the 1,000 Needles from FF. I tooled on the boss by only using that twice... after figuring out her really annoying attack pattern.
But, yeah. It's similar to 2D Castlevanias, but I'm going to say it's less straight forward 'vania than the past few outings. And that, my friends, is a very good thing.