Start the game with the hl.exe -dev
-console -game action command line. This enables the console window. You
can enter the original Half-Life missions with Action Half-Life's
weapons and models. The scientists, aliens, and Barneys are the same and
are fun to kill. When you enter the single player mission, display the
console window and type sv_cheats 1 to enable cheat mode. Then, type
/god for God mode, /impulse 101 for all weapons, /noclip to fly around
through everything, and /notarget for everything to ignore you.