I used to be a game reviewer, for about 80% of the games on the market you're right. However, some just make it all their own and it can be on a per game basis.

I used to be a game reviewer, for about 80% of the games on the market you're right. However, some just make it all their own and it can be on a per game basis. Diakatana was obviously a Quake II engine game, Anachranox was not. The engine was so heavily modified and doing things no one thought an FPS engine could do, everyone I talked to was surprised when they found out it was Quake II.