Way to complete the Game Expert achievement in Game Dev Story

Review scores don't seem to affect your chances; only the game's stats. Also possibly the game's combination, but you should never make a game that doesn't have an "Amazing" combination (more $!). I'm not sure whether or not creativity has a bigger influence on your Grand Prize chances than the other stats. Also, review scores don't mean anything anyway. If you save your game right before you kill the last bug, and you get a review score of 37, restart the app. You might get a review score of 36. Restart again, you might get a review score of 40.

The "game" ends after year 20, in terms of getting your assets in the highscore list. You can play indefinitely after this however, if you wish. The point is to make as much $ as possible the first 20 years.