Neuro Hunter

Dead man walking
Save in the moment of dying and load.

Effects:
 * You do not take damage at all.
 * Enemies don't attack you.
 * Turrets will still attack you, but you'll take no damage.
 * Pressing ESC will cause you not to be able to return to game (as if you've died).
 * Effect can be cleared by eating / sleeping etc.

Sleep walking
Right before dying, use a bed to go to sleep.

Effects:
 * You can walk through walls and any level geometry.
 * You do not fall.
 * You do not take damage at all.
 * Enemies don't attack you.
 * Can be converted into dead man walking by quick saving and quick loading.

Negate fall damage
Save right before hitting the ground and load.