Core Design, the makers of the original game in 1996 were the original makers of the remake, it was over halfway finished and even a trailer was leaked but it was canceled due to funding and Crystal Dynamics took over soon after.
The levels are much smaller but more detailed than they were in the original, for example players can discover more than just one path for Lara to take.
Cowboy was the only character from the original game not to appear in this remake. However the character was merged with Larson into one being.
Lara names Larson, indicating they met before, whereas in the original this is not indicated. This change may be due to the events in the first section of Tomb Raider: Chronicles (2000).
During one of the director's commentaries, Toby Gard and Jason Botta say that they didn't put the Ark in the foyer of Croft Manor like in the original game. One reason was that they weren't sure if there were legal rights to the Ark from I predatori dell'arca perduta (1981).