On the title screen, type "IEHOVAH". The screen 
should flash. During the game L will skip levels,
and 1-2 will go to the halfway points of the level.

Use a Hex editor to edit the file INDY.COM and find
the following bytes.

For infinite lives:
search for 08 3E F0 03 00 74 03
change to 08 3E F0 03 00 90 90
search for E8 15 4A
change to 90 90 90
search for E8 1D 4C
change to 90 90 90

For infinite energy:
search for 28 06 EF 03
change to CF 06 EF 03
search for BF 26 04 80 7D 0A FE 72 01
change to 90 90