Do you want to have all weapons into Lara's demo?
To hack TR2 you must open
your savegame0.dat file ( save it at the beginning) and change these lines:

080    000C FFFF FFFF FFFF FFFF FFFF FFFF FFFF
FC0   E803  0000 0AFF 0000 0BFF 0000 0CFF 0000
FD0   01FF  0000 0DFF 0000 0EFF 0000 0FFF 0000