So I tried this new demo... And I gotta say, this game has definitely improved...
Rego, I don't know if you programed the physics of this game, or not, but they are excellent. Especially convincing is Sonic's rate of acceleration. I also like how Sonic's top speed isn't a zillion miles per hour.
I noticed that you played down the dash panels in this demo. That's good. In all the situations where they were used, however, Sonic was fast enough on his own to progress through the level.
The graphics and sounds, though pulled from existing games, are used very harmoniously. The level theme is excellent, as I've stated before. Congradulations on composing such a pleasant tune.
You did have several multiple paths, as promised, including ones that that can be accessed at any time, and those that depend on proper homing-attack maneuvers. I personally don't like 2D Sonic games with the homing attack, but you've integrated it well enough that it's not a major issue.
If you are going to have the homing attack, it should target springs and item boxes as well, not just enemies. Sonic's sliding attack is nice, but should also break wooden boxes. Also, sometimes when I tried to spin dash, I ended up jumping instead. I'm sure that's just a little glitch or my mistake.
The lack of interactive gimmicks (aside from rails and the wall-jumping walls) is a little troubling, but this is one level in a demo. I'll look forward to what you decide to do with future levels. On a somewhat similar note, enemies should pose a bigger danger and function more than just homing attack targets.
Very good job overall. I feel you're 80% there to building a solid foundation for your fan-game. Therefore, you earn my rating of 4/5.
One more piece of advice: If somebody offers you constructive criticism, seriously consider it. It's fun to bask in uncritical praise, but that won't improve your game.