A good game, but could use some polishing
This is a really good game and a decent take on the real thing, but there are some problems that could use a little touching up. First of all, the player character is much closer to the front edge of the screen than in any real Sonic game, which limits the player's visibility. The sound and frame rate are a little choppy, but it's not too bad and it's probably the best quality you can get for Sonic on a flash engine.
My main complaint, however, is the lack of a very fundamental element in all classic Sonic games. When Sonic gets hit my something, there is usually a moment of flashing invincibility. This allows the player to survive obstacles such as spikes. With the lack of that element, there is a new unneeded obstacle. But, it's still a good game as far as flash goes.