Las Vegas is a complete map converted to GTA1. This new map (.cmp) contains new textures (style***.gry/g24), missions (mission.ini) and menu design. Includes new menu files: .raw and .fon. Using mission.ini, many surprises are included in the game (explosions, car hunting, killings, etc.). According to the author, you can fly a helicopter (which, admittedly, was in the game, but did not work).
All files must be thrown into the gtadata folder located in the game directory.