I'm kind of angry right now because I had this typed out but I hit some shortcut for backwards/forwards on my internet browser. But what I'm here to say is that I went to an event in England called Brick Live 2016. There was a 2PM panel about LEGO Dimensions that showed off some of the Sonic Level Pack. Here are some of the things that I noticed:
When exiting the level, the bottom left corner only read 0/9 instead of 0/10. This will probably change in the final release, but I thought I'd mention it anyway.
Also when exiting the level, the text "Big the Cat Rescued!" appeared on screen. This may or may not change in the final release.
The dev from TT Games stated that you would have to collect all seven Chaos Emeralds to transform into Super Sonic.
As with the trailer, studs were changed into rings, which were both silver and gold.
On the battle arena selection screen, an arena named "Casino Night Zone" appeared briefly. The description was some kind of file name in caps with underscores.
The intro Cutscene started pixelated then changed into LEGO bricks, with the classic title screen but with Sonic's Minifig.
When you try to pilot the Tornado, Sonic will hop on the front and Tails will appear out of nowhere to drive it.
When asked, the dev from TT Games stated that they are likely to work on more Sonic Packs in the future.
I lack any video or photo evidence to prove this, so you're just going to have to take my word for it.
If any of you also went to the event and saw something I didn't mention, please post it on this thread.