There is a perk that enables critical hits with quickhacks. But most quickhacks don't deal direct damage. Do critical hits have any effect on quickhacks like Suicide, Weapon Malfunction, Cyberpsychosis etc.?

My 2 favorite Quickhacks are Reboot-Optics and Contagion.
With Contagion, I get 13 (ticks) of damage that happen over time. This is also true for the Overheat hack when i use it. Even when i use Short Circuit, Once in a while, the damage starts off at a much higher starting point - regardless of the weak/resist of the target.

I'll start looking to see if it changes the duration. It possibly reduces any resist the target might have.

Honestly, I don't know, these are totally just observations.

If it performs as stated in the description it just has a chance per tick/damage dealt to do a crit with any power that deals damage.

No reason it would do additional damage for anything that doesnt directly deal damage.

To see your chance, which is moddified by any mods or implants, goto Character -> Stats.
Crit chance and crit damage there show what it should do.... eg 48 crit chance for me and 104 crit damage.

It's a very powerful perk that allows any damaging hack, DD or DOT, to maybe crit depending on your crit rating. for double or more damage.

That perk + the other damage perks + the spread distance and number perks + the the general poison damage perks from the cool tree turns contagion into something that will outright kill 7 or 8 bad guys even on different floors, in one go easily.

I was seriously wondering about that... i see no point into poison but then i started seeing a TON of weapons with poison dmg on them and then contagion popped into my head... i think im going to make a stealthy hacking poison guy next!

The contagion hack doesn't do tons of damage early, but after you start getting hack perks, it does wonders. Especially the cool downs and recovers for terminated infected people.

It's fun in a demented sort of way to watch your virus spread and many times back to the original host.

Even better after you get a legendary "Ping" that allows targeting through walls and floors. I've cleared whole 3 story buildings of all bad guys before I've even set foot in the building. I then just go in pick up the loot and do whatever I went there to do :)

Same cameras and turrets off, I do find it quicker using Reboot optics and KO using Electric Baton to the face it's very quick.

I thought the legendary hacks were broken?

Broken in what sense? Every legendary I've crafted and used work exactly as described. Unless you mean "broken" in the sense of being overpowered because they really are that,

No I meant bugged as in didn't work.
I saw someone post something to that effect shortly after release time.

They all work just fine but I didn't do much hacking first time through. I didn't start playing a hacking build with epic and legendary crafted quickhacks until after 1.05 so maybe they were wonky at first. Never saw that myself though.

They've always worked fine for me.

I have finally gotten to legendary quickhaks and they work good for me too. :-)

Hide and do weapon malfunction over and over and see how many weapons they can drop.