Like the first, the second game was a commercial success, green-lighting a third game. Production of "Crash Bandicoot: Warped" began in January 1998, with Naughty Dog given only 10½ months to complete the game. Programmers Andy Gavin, Stephen White and Greg Omi created three new gameplay engines for the game. Two of the three new engines were three-dimensional in nature and were created for the airplane and jet-ski levels; the third new engine was created for the motorcycle levels in the style of a driving simulator. The new engines combined make up a third of the game, while the other two-thirds of the game consist of the tweaked engine used in the previous games. Jason Rubin explained that the "classic" engine and game style was preserved due to the success of the previous two games and went on to say that "were we to abandon that style of gameplay, that would mean that we would be abandoning a significant proportion of gamers out there". An arbitrary plane z-buffer was created for the jet-ski and flooded Egyptian hallway levels of the game. To create a completely fluid feel for the water on these levels, an environment map that reflects the sky was fitted onto the surface of the water. A real shadow was given to the Crash character at the request of the Sony Computer Entertainment America producers, who were "sick of that little discus that's following him around." To create an "arcade" experience in the airplane levels and to differentiate them from flight simulators, the enemy planes were programmed to come out in front of the player and give the player ample time to shoot them before they turn around and shoot the player rather than come up behind the player and hit them from behind. The Relic system was introduced to give players a reason to return to the game after it has been completed.