Well this game comes with very little info. Simply try to win races and buy better cars as you go along. Races, and tournaments open up as you win more and more.
Steering is with directional keys, and that's it. Don't expect there to be anything beyond that. Oh, of course always expect to be addicted...!
Pater Alf : I don't think this is a verygood racing game. When I play games in this genre there are just two things I really need: A great variety of tracks and cars with a nice vehicle handling. GT Challenge lacks both. The tracks are all very similar and the cars don't behave like cars at all. When you bump in something or something bumps you, the cars don't break out or move to the assumable direction, but simply slow down. That doesn't make sense at all and is annoying after a while.
Game is still playable though, because of the nice career mode.
Drasir-Vel : I picked up this game and tried it. It does seem quite simple. When you bump into something it's not like your car recoils from the impact. It's more like the car resets it's heading to something else. That was annoying sometimes. There are a good number of cars in the game, and the performance of them increases steadily as you get up in ranks and complete the cups. Different cups and championships unlock as you complete the ones before. The tracks however are only different in how the track goes, meaning there are no difference in themes or scenery, so that can be repetetive.
Even though it doesn't seem like a game that's better than most, i still found myself playing it to the end, getting the best car there is, and completing every single championship. Maybe that's because you can make progress in the game, and earn money to get better things. That has always been something i liked in a game, like in NFS Road Challenge, (also called High Stakes in the US).