I been playing this game for a couple of days now and I'm quite pleased actually, the game is faithful to the original games... Almost too faithful "that damned maze level 7 https://www.youtube.com/watch?v=ZPAcUzwjUlg
The gameplay is good, all of the old moves are there such as konais, wall jump, ceiling walk, double jump, double jump attack, sword attack, air kick attack, the crotch walk was replaced by a slide and they took away the sword short-jump attack which is a shame, I like how the konai respawn though it's a lot more handy than the original games.
Alongside the usual moves they added lots of new ones like the spinning sword attack and the , same spell move, the explode spell is replaced by a weird black spell that doubles your konai attacks and makes them respawn faster but drains your health faster, and the water spell replaces the duplicates spell in the original though it does pretty much the same thing, which is making him faster and jump higher.
Cutscenes are probably the best part of the game, they're little cartoony section and while aren't fully animated most of the time, which is a shame yet expected since as far as I can remember SEGA never did a good job with animated cartoony cutscenes in their games not even Sonic CD and that was their best work (usually Konami are known to make the best cartoony cutscenes) still they're not bad and always entertain you between levels, here's a link if you want to see them https://www.youtube.com/watch?v=qDaUnYbVAps
Graphics are good for a 3DS title, like really good, I like 2.5D games that do it right, there are bits where the level turns while you're walking to make you turn along with it which is a nice effect.
Legacy, some of the levels make a return like the horse riding level which makes the view from the backside instead, the surfing level is back too but it was a little disappointing (at least to me) because of the force of using motion controls, there's also the highway on-cars level from the original game, the mutated brains are back too and the on board of the battle ship too, I was expecting they'd add the level from the original with the fence that if you jump you get to the other side but it's not there unfortunately, I was hoping for Spider-Man to appear again but I guess it's a long shot for them to do that anymore =p