Final Doom is really the third Doom game, so Doom 3 is really Doom 4. Anyway, This game is great. Thirty brand new levels, with tons of tricks and surprises. The only drawbacks are that there are some invisible walls which demons can attack you through, but entering these walls can be fun. Also, it seems like you can never pick up a key or open a door without a wall opening up with a dozen monsters behind it ready to attack you. But the gameplay is flawless. I highly recommend this game!