From IGN Pocket:
The game wasn’t playable, but it was running on Game Boy Advance hardware through a Wide Boy AGB device (you know, the development cartridge that enables developers to play GBA titles on an N64 and a television) as a self-running demo. And man, it was slick.
The Game Boy Advance title, developed by Dimps, is based on the classic side-scrolling design, but it’s a game all its own. Sonic can run and jump, as well as spin-dash to get himself out of specific binds. Collecting rings is still the name of the game, and when you get hit by specific enemies, dozens of those golden ‘o’s go flying–showing off the GBA’s sprite handling capabilities. The game is super-fast as it should be, and there are plenty of corkscrews and loops to make players going dizzy.
But that’s not all – the game also borrows from the second Dreamcast adventure – Sonic can now “grind” down rails in several places in the game. Though the demo only showed one instance of this feature, it was a lot of fun to watch. The graphics have also been completely redone, giving the hedgehog an edgier look to his classic design. And the pictures that Sega has given us show that you’ll also play as several different characters as well – Sonic, Tails, Knuckles and Amy will be in the player lineup. And, like a good GBA game, it will support the four player link for multiplayer mini-games.