It's a great game. Not perfect, but that's what GT5 is for (well, that won't be perfect either but you know what I mean). But it's the best driving game I've played for some time.
My only real complaint about GT5 Prologue is the penalty system. It just doesn't work. Online, yes, it makes sense. Offline it's far too arbitrary and inaccurate.
Many, many times have I been penalised when a car hits me. It's not always from the rear either, often when side by side and when I am on the racing line. Or penalties for "shortcuts" when I'm sliding into a barrier!? AI cars are immune to penalties even though there are always some that are erratic or make mistakes.
The AI is much better than in previous GT games but they should be subject to the same penalties that the player is. This, of course, has not been programmed in. And you should see how far off the course they go and how inconsiderate they are when trying to get back onto the racing line you are currently occupying!
Now of course you can get through a race without penalties. But many times have I aborted a race because of a penalty for something I did not do wrong.
I hope and pray that it doesn't make it into the final game because if it does I am going to be very unhappy. If car damage gets rid of the need for this very unbalanced and seemingly partisan penalty system then please let GT5 have damage. This badly hampers the enjoyment I take from what is generally an excellent game.