They're different from Sonic 1's. You control the rotation of the stage, not Sonic himself. Also, the whole ring gates and time limit thing. And Hidden Palace Zone, where they just reused LRZ2. Which isn't Sonic 1, 2, 3, or Knuckles.
I was thinking level design, hell I'm sure I expressed that in my post (okay, I did, but perhaps I should have worded it better). Out of the list you've supplied, I can see "Running on water" as a new interactive part of the level. The snowboard is more of a one-off, in the same sense that certain elements of Sonic 1 & 2 were one-offs. Of course, with every new game, new characters and objects will be implemented, such as the Master Emerald, and Knuckles, and things like that. Having Death Egg as an actual zone doesn't really constitute as something that Sonic & Knuckles brought, because the Death Egg was just a zone to begin with. In the same way I could say that Sonic 4 gave us The E.G.G Station. You're right about the shields though, although that's not really part of the scenery/physical level design. Edit: Because Sonic 4; Episode 1 is the equivelant of Sonic 3 in this new continuation, it's difficult to compare it to Sonic 3 & Knuckls, although comapring it to Sonic 3 would be a much better idea. That way, comparing things like Doomsday Zone can be saved for later, considering that Sonic 3 (part one of two) didn't have it either.
So wait, if a feature that was in Sonic games from 1999-2009 and it shows up in Sonic 4, it's new? Did not know that. :p
"New" in the sense that it's the first time it's been included in a classic(ish)-style Sonic game (that isn't a ROM-hack or fangame).
The HA in S4 is very different to the HA in previous 2D titles, bar the Rivals games. It plays a huge part in the design of S4 and was merely a fun extra (like the insta-shield) in the Rush and Advance games.
It was in Advance 2 and Advance 3, which are by no stretch of the imagination classic-style Sonic games.
Advance 3 is pretty classic once you take the multi character system out of consideration, just not as much emphasis on physics as was in Advance 1
It leans a lot more toward Advance 2's style than Advance 1's style, but it's closer than Advance 2 was, at least.
I was really confused when I first noticed it, it was my second playthrough of Casino Street Act 3. There was a cannon right after a checkpoint, and I just let Sonic fly through the air and he just fell into a bottomless pit, so I did it again about 3 times just to check if I hadn't gone mental seeing Sonic kill himself.
So I downloaded the trial today since I don't have any money for a points card, and I love it. I can tell the physics are off slightly from the classic games, and my girlfriend and I got a kick from Sonic standing on a slope randomly, but I rated the game 5 out of 5 stars. I can't wait to get the full game. :3 Though I wish it downloaded quicker. :v:
Hooray, I finally got this game. I beat it in 2 hours with all emeralds and 120 lives to spare. All that's left are the achievements. Geez, everyone was right about this game being too short.
Too short, but there's something about Sonic gameplay that makes it so goddamn replayable even when it's kinda "meh" on an objective-quality level. And actually, I've been seeing some of my 'net acquaintances who found the game underwhelming at first come back later saying stuff like "You know, I've been playing Sonic 4 again, and for some reason it's more fun now." Which is a relief. The game's been getting steadily and steadily more entertaining as I've played it, and I was afraid it was just me going insane for want of a true classic Sonic game or something. =P
