NFS presented maximum colour to a DOS game, plus it was the coolest racing game ever that created a loyal fan base.
The typical arcade-racing games are based on two things-- diverse and scenic race tracks and cool wheels. NFS did both this job with highest sincerity. During that time you could not find a game with so beautiful race tracks. With cool cars around, the racing opponents were designed to give you such a hard time that you would get back to the game again and again till you win each track by a second or two. I played this game first as a demo in early 1996 (back then a 5mb demo seemed a really big file) and the full game in 1997. So I can't exactly recall the number of tracks or the available cars. But my feelings for this game lingers on. This proves the success of this game. Plus I have loyally picked all of the NFS /Underground games and eagerly wait for a new installment each year.