Thanking the developer, this is one of the only web player racing games I really 'enjoyed'. Brilliant physics, loads of hard work (hopefully), nice lighting :)].
A 5 star game: Improved visual effects i.e motion blur, making the vehicle actually look 'fast'. Improved AI (CPUs). Atleast 5 tracks, which will be real fun for free roaming :). Physical car damage. Fun stuff like smoky burnouts, and a bit more game modes. Sure go for multiplayer (atleast for free roam). Manual free camera rotation (without making the player drive). If all or some of this happens, this is gonna be genuinely brilliant, and is still fun :)
PS: Try driving and stunting around holding 'R'