Mechanics which have positive feedback. More specifically, this refers to wound mechanics which give a penalty to all combat rolls. This means that once wounded, a character is more likely to be wounded again, and soon there is an inexorable progression to defeat.

In terms of dramatic pacing, this means that combat will tend to be anticlimactic. That is, the side with an early advantage will tend to win out.

It can be argued that this is realistic for wounds, but in general most wound damage in reality takes at least a minute or two to set in as the adrenaline wears off, and blood loss and shock take affect.

References:

• Techniques for Action Pacing in RPGs
• Gamism: Step on Up