Wow! I wasn't expecting this at all when I started playing. I'm going to skip the part where I don't understand how you transferred 3d graphics into a flash game because I know nothing of code, but purely concerning gameplay, bravo! The controls are smooth, the menus are mostly easy to navigate, and the flashback feature is AWESOME! I am Racecar God, and none shall oppose me! The programming skill that went into creating this game is apparent from the get-go, and continues to impress well into your 10th, 20th, or 30th race!
That said, it does still feel like it needs a bit of polish sometimes. I was a tad bit confused about whether or not I was playing the multiplayer mode with actual people, because when I did the time rewind thing... it worked. Which seems unlikely and/or really cruel to everyone else I was supposedly playing against. There were a few moments of lag or general rough handling as well, and I wasn't picking up sound, but that may have just been me. I also felt that a little more control could be added to the driving, such as a handbrake to enable some sort of drifting or other skill-based maneuver.
These few tweaks aside, though, this game has the charm of a retro N64 title with a cool, modern-day game mechanic that keeps it interesting and elevates it above a simple racing title. It's definitely something I would have played in my school's computer lab all day when the teacher wasn't looking, as I'm sure someone is doing right now.