Unbelievable realism but has some glaring issues that need to be fixed in the final version
There are a few issues here though, firstly there is steep learning curve, probably because there is not the large amount of events as in a full GT release. So after about 20 C and B events the A events get significantly harder, as do the S events once you beat that. Also you will need to play events a few times (or play online) to generate all the cash you need to play all the events, as some require specific cars forcing you to buy them to be able to complete the game.
On the topic of the events, you always start dead last (qualifying has been removed, however I'm sure they will add it back for the final), which is a great challenge but can be a huge exercise in frustration as the developers have added some "features" that need to be polished and/or possibly some bugs. Firstly the AI is better than in previous GT games and seems to more genuinely react with the situation. However they are not shy about wanting to be where you currently are. Which brings me to my next point, penalties. GT5 has introduced penalties in all later races similar to how GT4 has them in rally events. This nets quite a bit of frustration.
The problem is the penalties do not apply to your competitors, so if you hit them you are slapped with a 5 second penalty, but they can beat you up all day long without slowing down. As well if you get bumped into the dirt you come almost to a dead stop sideways, while your competitors fly right through it like its still road. However, the most frustrating of all is the shortcut penalty. If your car crosses the border of the track by more than halfway (with just 2 wheels off) you receive a 5 second shortcut penalty.... Even if you are spinning sideways off the track, even if someone punted you there! As cars are blowing by you you are stranded for an additional 5 seconds making a situation you maybe could have salvaged into a top 3 finish, an impossible win. If they are going to have a feature like that it needs to have a little more logic behind it or it will ultimately frustrate and turn off players. If you are doing one of the one-lap mission stages (pass 16 cars in 1 lap) and you get any of these penalties you may as well give up.
Overall there is a lot of promise in this game, and GT fans won't be disappointed. There are a lot of features of GT missing but that is to be expected, as its the Prologue. I am sure they will be added. The graphics are photo-realistic, the car sounds are wonderfully perfect, and the control and handling is dead on. That said, due to the issues above, you will be hitting the "reset" button a lot. I only hope that the developers update or fix the new "features" to make it more fair to the player and GT5 will become the Perfect racing game.