As a racing gamer for 4 years, here's my quick review:
This is not a heavy game, which is awesome to every devices in terms of performance. The track environments are aesthetically remarkable, the music is fun and suits the game and the dev very well. (Big ups to you, Evan King). And all of the contents are available for free (That's a great price!).
a big issue with the game for me is the physic. it does work at a degree of view, however, the car keeps flinging sideways and there are no ways to control the car, even at low speed. Gripping is even harder. Once the car starts drifting, there is no way to adjust normally; instead, it either drifts off the track or makes a spin. It's best to either brake or releases the gas before the corner to make the best cornering speed, because there is no way braking or releasing gas can stop the car from moving out of the track. Worst of all, especially for the initial D fanboys, the inertia does not work as a simulator, but rather arcade, so spin and drift, but no Scandinavian flicks or inertia drifts.
The second worst issue is the bot. Accounting for the same speed, but more grip, more weight. Slight contact can spin the player's car off track immediately. And the bot does not drift like the player, so there's no way to push it off the track beside me, the player. At this point, it's less of a driver bot and more of a 1-lane width moving annoyance.
Overall, had the most fun messing around with this game for drifting-jumping stunts, but not recommended for racing/time attacks. Maybe adding drift challenges would be a lot cooler for a game that emphasizes drifts over grip. Multiplayer, too, could be a fun addition for different players to do stunts together, like drift battles or tandem.