The monowire is a melee weapon with a charge meter that provides bonus damage that depletes as you attack. It can can be used for both a simple attack (pressing the fire button) and a strong attack (holding the fire button and releasing when ready to attack). A simple attack will swipe across the screen in a frontal cone, hitting all enemies in its path while the strong attack will whip the monowire forwards and do a double attack on the enemy you're aiming at. In testing both of these attacks seemed to randomly miss one of the attacks quite frequently even when it looked like they shouldn't. Both of these attack modes are very close range.
The charge level acts a lot like the stamina meter but is not impacted by any of the traits that reduce stamina cost or increase stamina regeneration (including the ones in the Street Brawler perk tree). Each attack uses some of the charge level - a simple attack will use up to 20% of the remaining charge while a strong attack will use all remaining charge. The charge meter will begin recharging after a moment of not attacking.
Attacking with no charge still causes damage, but without any bonus damage component. As such the monowire works particularly well at 100% charge from stealth on an unaware enemy with the appropriate perks selected to increase damage from stealth.
The current charge level is shown on screen next to the reticle.
Monowire gains a +3 damage increase per "Cool" attribute level and 1.5% damage increase per "Body" level. It is unintuitively classified as a blunt melee weapon in terms of the damage it does but this does mean that it gains bonuses from the Street Brawler perk tree - in particular Flurry, Frenzy and Crushing Blows will give quite the damage increase. You can also capitalise on the stun based perks in the Street Brawler perk tree to give you a chance to stun enemies when you attack and in turn do more damage to stunned enemies. Monowire also benefits from other perks that impact melee damage, such as Blood Brawl under the Cold Blooded tree. Neutralising enemies with the monowire will level up the Street Brawler perk tree.
Monowire also synergises well with the Beserker cyberware, which in turn can be augmented by using the Beast Mode mod to further increase damage while Beserker is active. Monowire can be further boosted with cyberware mods - adding a high capacity monowire battery will increase monowire damage by a further 50% and sensory amplifiers will increase your critical strike chance and damage.
The reason why you're probably dismembering some enemies while only incapacitating others is probably down to the wild variance in enemy strength you can find just by walking around - especially before you're level 40 or so it's entirely possible to have a side mission that is easy enough for you to kill everything effortlessly surrounded by a number of other missions that are 10 levels higher than the mission you just did. It's also possible it's simply down to buffs - the Street Brawler tree provides many temporary buffs (such as temporary damage increases on kill) that would increase your damage output over the duration of combat if you're chaining multiple kills together.
