LogFAQs > #966219139

A summary of their time with the game(via a site no one wants to visit):

Controls were complemented multiple times. "Smooth and fast but not unwieldy", "Jumping is precise". "Speedy by controlled".
The game starts with a cyber space level based on Green Hill Zone. You reach the open world afterwards.
The cyber space levels are number. 1-1, 1-2, 1-3, etc. The first one worked as a tutorial and was done in "less than a minute".
1-2 is "Unleashed inspired". 1-3 is "metropolitan" - probably the one from the trailer ? -. Other levels are inspired by Green Hill (again) and Chemical Plant.
Sonic Team listened to the criticism of the past few games being too short and think that Frontiers is a significant improvement in this regard.
No mention of other islands in the preview, but they found Kronos Island to be quiet large. " Quell any concerns I had that Sonic would be able to speed across too quickly".
The main loop is getting Portal Gears by defeating bosses => Using them to unlock Cyber Space levels => getting Vault Keys by finishing the Cyber Space level different challenges => Using them to unlock vaults containing the Chaos Emeralds.
You can increase Sonic's strength and defense by collecting seed and giving them to the Hermit Koco. You can increase his top speed and ring limit by returning lost Kocos to the Elder Kocos. You can fast travel to them once you've met them.
Big is in the game. Teaches you a fishing mini game.
Amy gives you quests when you hit different milestones in collecting her hearts. They center on helping Kocos. One they found especially difficult included leading several lost Kocos back to their mother while avoiding explosions.
They enjoyed the boss fights variety. The Flyer boss fight was one of their favorite moments in the game.
"Shows more potential than I can recall for any 3D Sonic game".

Time to catch the Froggy!