Here's a summary of the stuff I talked about in part 1 of my little "Sonic 06 Press Conference" Note: I only played through 2 stages and 2 boss fights as Sonic.
1. The camera still has issues, but thanks to the auto center button, is considerably less painful to deal with than SA:2's awful camera.
2. The get rings to increase speed thing has been grossly exagerated. You don't need many rings to go fast.
3. The homing attack now requires timed presses to get the most out of it.
4. I went through 2 stages; Wave Ocean and some desert level. Wave Ocean was a pseudo re-mix of Emerald Coast. About 1/3 through the level, you play as Tails. He's slower than in SA but he has this fake ring attack (must be airborne to use) that explodes on impact like a ground bomb. Your objective as Tails is to find a switch (looks like the knob like switches in SA2). The mach speed section is like part 2 of SA's Speed Highway (Sonic) and was cool. The desert level gives you the ability to use Princess Elsie's special power to prevent you from sinking into the sand (instant kill BTW). The level designs were quite fun. They're also considerably longer than a typical Sonic game. Despite getting an S rank on my first go (partially due to my inherent instinct to crush all enemies in my way), the desert stage took about 4 minutes to finish.
5. The enemy and boss designs are cool. The robots actually look dangerous, the kind of robots I'd want to fight again and again. The first boss alone was one of the coolest bosses in years. (So far from what I've seen of boss designs, they look like stuff I would throw at players if I was in Sonic Team.) It was called Egg Cerberus and it looked like a giant wolf.
6. Be careful, Silver can juggle you if you're not careful.
7. The adventure segments are an improved version of SA. You get a mini map in which stuff that's important is designated on the map.
8. A word of caution. Check the shops OFTEN, you'll need to purchase special powers to get past certain sections.
-In response to ks8's questions, I haven't explored multiplayer yet (rarely do so). I usually check what we can compete in after clearing last story (BTW, the initial ending in last story is NOT the real ending), so I'll probably get back to the rest of those questions by next week.
-I'll be starting part 2 of my press conference, covering Silver as promised.