I spent a week testing the requirements for "Traceless ICA Assassin"

Freelancer disabled the Silent Assassin rating so that players would focus more on completing the mission objectives and experimenting with the game's systems rather than worrying about not getting spotted or only doing silent kills. However, in its place, they left "Traceless ICA Assassin". This is the highest possible rank you can get on a Freelancer mission, achievable by completing the requirements for Silent Assassin during a run and also avoiding "leaving a trace". But what exactly does it even mean to leave a trace? What actions can you take that will void Traceless ICA Assassin, and leave you instead with Clean, Stealth, or Shadow Assassin? That's what i spent the last several days trying to figure out.

Below is a list of common actions that I have been able to verify will make you lose your Traceless ICA Assassin rank, even if it doesn't make sense at all:

• Pacifying NPCs with Bananas/Grapes left on the ground
• Lethal Syringes
• Emetic Grenades, Chloroform Flask (thrown), and the Flashbang Phone (when used up)
• Explosive Ducks and Breaching Charges
• Igniting an Oil Canister spill
• Firing an Assault Rifle, SMG, or Full Auto Pistol
• Turning on Environmental Distractions (except sinks)
• Lockpicking Cabinets, Lockers, or the Whittleton Creek Garages
• Letting guards find a gun on the ground
• Letting a dead body from an accidental/poison kill be put in a body bag
• Letting a tranquilized NPC be woken up
• Entering Combat for any reason
• Using a Showdown Meeting Phone
• Causing a Showdown Suspect to escape
• The Gun Lure Glitch
• The Phone Lure Glitch
• The Pistol Mudshot Glitch

None of these actions, if performed in the main story, would void Silent Assassin, which means Traceless ICA Assassin is actually harder to achieve than the previous highest rank in the game. I dont believe IOI intended for it to be so unforgiving, and instead just used Traceless ICA Assassin as a "default" ranking for players that didn't achieve any other rank. All the things that voided your Traceless ICA Assassin rank were probably not given much thought, considering ranks don't matter in Freelancer.

In my testing however, i did find a list of notable actions that will not void Traceless ICA Assassin, and so can be used during runs:

• Emetic/Sedative Syringes
• Concussive Ducks
• Emetic Gas Device (even in a briefcase)
• Water Canister + Remote Micro Taser kill
• Proximity Micro Taser pickup kill
• Firing Pistols, Dart Guns, Shotguns, and Snipers
• Firing a Loud Pistol (even if heard by a guard)
• Using a Sniper or Shotgun to blow open a door
• Using the craftable Makeshift Remote Explosive Device (so long as no one hears it)
• Turning on sinks as a distraction (and possibly every "legal" environmental distraction)
• Shooting a propane flask
• Shooting a falling object
• Any accident kill so long as the body isn't discovered
• Unlock Keypads and the Chongqing Vents
• Calling someone over as a bartender
• Knocking out a lot of NPCs
• Letting guards find a briefcase on the ground
• Being seen on camera and deleting the evidence
• The Peekaboo Lure

Its funny how this ranking, more than Silent Assassin itself, encourages the boring gameplay of "use coins to lure and pacify 20+ NPCs so you can fiber wire the target unseen". The fact that this ranking also discourages accident kills, despite the fact they're way more "Traceless" than shooting a person in the head, is also insane. Again, I don't think IOI put much thought into the parameters for this ranking.

Finally, do note that there are a number of things that I didn't test. Mainly, the RNG lootcrate items. I dont know if using Napoleon Blownaparte or the Emetic Gas Grenade will void Traceless or not, but you're not guaranteed to even get these items during a mission anyways, so it largely won't matter. I also have a feeling that only the environmental distractions marked with "!" will void Traceless, but i dont want to comb through every single map to verify that.

Feel free to disregard this information and explode all your targets with Explosive Ducks. Its probably more fun to play that way.