Starting with version 0.99.8, there is a realism CVAR implemented.
It can be set from 0 to 5.

Realism Level 0:
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Locational damage disabled.
Head shots lethal to monsters.

Realism Level 1:
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Locational damage disabled.

Realism Level 2:
----------------
Realism level at default.
Bleeding damage.

Realism Level 3:
----------------
Head shots lethal to player.
Bleeding damage.

Realism Level 4:
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Cheats disabled (unless... well... I'll let you figure out how to turn
	them back on =D )
Head shots lethal to player.
Earlier ranks slower.
Bleeding damage.

Realism Level 5:
----------------
Cheats disabled (unless... well... I'll let you figure out how to turn
	them back on =D )
Head shots lethal to player.
Earlier ranks slower.
Bleeding damage.