Gridder

Alternate sprites:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 5578,0
SYS 4608

Unlimited lives:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
POKE 6757,96
SYS 4608

Unlimited lives (alternate):
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
Poke 6757,173
SYS 4608

Select number of lives:
Load or reset the game, then execute the following BASIC commands before running or restarting the program.
Note: X represents the desired number of lives.
POKE 4704,X + 128
SYS 4608