I'm curious what combos people are pulling off to unlock this one, mine was:
Ambuscade -> Tachyon -> (Synaptic Interruption) -> Stealth Bot -> (Lead From the Front) -> Legacy -> (Stealth Bot) -> Stealth Bot -> (Smoke Bombs) -> Tachyon -> (Synaptic Interruption) -> Ambuscade
This is by far my favorite achievement, it was fun to both think through how to do it and then to go about pulling it off.
We did Ambuscade to Tachyon -> (Synaptic Interruption) -> Nightmist -> (Amulet) -> Raptor Bot -> (Smoke Bombs) -> Tachyon -> (Synaptic Interruption) -> Legacy -> (Stealth Bot) -> Stealth Bot -> Legacy (Lead from the Front), so we actually had 1 more than we needed.
This is perfect! What was the environment? Or does it not matter?
It doesn't technically matter, but if there are things that deal damage to lowest HP, that can help by making the first redirection via smoke bombs "free".
Neither lead from the front nor smoke bombs redirect damage from environment targets. It'll almost certainly have to be damage from a villain target that gets redirected. Any environment that doesn't harass your ongoings or equipment is fine, though you could make a case for Wagner Mars Base so the meteor swarm gives you all the time in the world to set up.
This is why I chose Ambuscade and The Block. Neither one messes with your stuff, and The Block just fights with itself most of the time.
The easiest way I found requires Baron Blade, Visionary, and Tachyon. Tachyon must be the lowest hero target, and Baron Blade must have Twist the Ether played on him. Get out all three Synaptic Interruptions, both Elemental Redistributors, and then get Blade to play Slash and Burn.
Baron Blade attacks -> Twist the Ether (fire; not a redirect, but necessary)-> Synaptic Interruption -> Elemental Redistributor-> Synaptic Interruption -> Elemental Redistributor-> Synaptic Interruption
When I did this, I also used Lead From the Front to add an extra sixth layer on.
I've tried this twice and every time it screws up at the Legacy -> (Stealth Bot) portion. I'm not sure if it's a bug or I'm just missing something but instead of redirecting the damage to Legacy it just deals 3 projectial damage to Legacy. I got around this by allowing to redirect to Stealth Bot, then Legacy can Lead from the Front. It was realy weird because it even said it would redirect to Stealth Bot but it just didn't.