Found this on a list of AAA video game titles with source code available. It's really amusing to look through, relatively bare bones C. Very funny comments and last minute changes due to play testing:

    #ifdef PSX_VERSION
     int  keepitopen=0; // MAJOR FRIG X 1,000,000

     // SONY AMERICA DIRECTIVE NO.A23
     // It is written: Everyone, given the chance, will jump off the boat, just
     // before they are about to completed the level, in order to play an extra couple of
     // minutes from their last save game. (They love it).  Add all such people together,
     //  counting each person as a brain cell, and you will have a brain about the size of
     // a Sony play tester.
    
     // Sorry Gav, but this had to be done!
     // Check if the boat has gone thru the door without lara,
     // if it has then keep the door open.
     if (objects[BOAT].loaded && lara_inboat==0 &&
      boatitem->pos.x_pos>24500 && boatitem->pos.x_pos<26500 &&
      boatitem->pos.z_pos>75500 && boatitem->pos.z_pos<83000)
      keepitopen = 1;
    #endif

Seems like it was made by a small group of programmers (at least according to GAME.h)

    #define ANDREWH 0
    #define GAV 1
    #define JASON 2
    #define RICHARD 3
    #define NUM_CODERS 4

Always a pleasure to go through code of a game that you loved playing and get to see how the magic happens. It's way "dirtier" than I expected. That says a lot about how games and (software that ships) are actually made.