MELEE
LEFT_CLICK on an active target character (any part of it), while having a melee weapon (or basically any item that can be used as one) in an active hand, will result in an attempt to make a fast hit (punch with something blunt or jab with something sharp) in the selected bodypart.
Suggestion: longer LEFT_CLICK should result in a slash attack for blade melee weapons (like swords),
longer hits with contact-type weapons (like stun-batons)
or stronger, slower heavy attack for weapons that rely on brute force (like hammers)
where the longer the time of holding the LEFT_CLICK, the wider the swing (or the longer the contact with the contact-type weapons, like stun baton or soldering iron).
The choice of the attack type might depend on the weapon’s primary (biggest) damage type or might be a completely separate thing, specifically programmed for melee.
Reference for how the melee fight should look/feel like pace-wise:
Reason for this is that in Space Station 13 the fights mostly consist of attacks that occur on click on the opponent, which means the fights are made with fast hits and instant attack startups in mind.