Realistically speaking, if you buy this game in the morning you will finish it by the evening. To complete the game you only really need 4-5 hours of game play. Although some of the missions are challenging (particularly the last), you'll only need a few attempts to get through them. The missions themselves are fun, although can be a bit repetitive (lose the police etc).
The graphics of the game are relatively good, although nothing extra special.
In the game you also have the option to "free roam" around Hazzard county, trying to get 5 stars on all the jumps and do time trials between places. However, you'll probably start to get bored of doing this relatively quickly.
Whilst free roaming, you might land yourself in one of Sheriff Rosco's "smokey bear traps," where he'll start pursuing you. If he does start chasing you then don't worry because he is so easy to escape.
The story line is a bit basic (although a typical J.D. Hogg plot), and involves the Dukes trying to save the Orphanage.
Overall the game is good albeit rather short and I would only really recommend it to a Dukes of Hazzard fan.