All Weapons and Ammo:
1.Walk one step forward

2.Walk one step back

3.Turn around in any direction three times

4.Jump backward

Skip to the Next Level

1.Walk one step forward

2.Walk one step back

3.Turn around in any direction three times

4.Jump forward

Note: In both cases, "walk" means hold down the walk key -- if you don't the cheats won't work