My one accomplishment in this vein was in TSW. I had a character who could kill small enemies (think the zombies in Kingsmouth) without attacking them.
It all came down to the combination of one active and one passive power.
The active power, Martial Discipline, increased the chances an enemy would glance me by 50%.
The passive power, which I can’t remember, made any enemy who glanced me take 200 damage.
So, I’d go to Kingsmouth, jump on a car, turn on Martial Discipline once the zombies (who had fewer than 200 hp) started to swarm me, let them attack me (inevitably landing glancing blows)…
…and watch them all drop dead while I didn’t lift a finger. It was such a little thing, but it delighted me.
Done some heart pumping crazy saves with flicker but i think the most epic one was against Eblis.
Everyone but me and another dps died right at the end. And i dodged and flickered around the circles of death, in an attempt to stear clear of Eblis long enough for my co dps to murder him in peace.
Get every weapon in the game to expertise level 50 because it’s the one easily measurable thing the devs forgot to include an achievement for.
Also, quite accidentally, solo finish the unbound ak’ab boss in Darkness War E1 on my fist/blood dps alt, partly because he decided to dash a lot rather than outright attack (so punching him while just staying out the lane was an option) and partly because apparently bringing Sanguine Coalescence as dps isn’t quite as stupid as one might think (as finally taking a swipe at me exploded in his face).
Being killed by mummies in The Dusty Dark & then being unable to pick up the torch. Then, spending an hour wandering in absolute darkness trying to find the entrance to the next zone. (I had killed 99 scarabs & exiting the zone would have reset the achievement.)
I figure there should be an achievement for Scenarios 10/10 survivors.
And as a prolific dimension jumper in TSW i’d love to see something like ‘transition your character through four different instances in a row beyond their original/home/starting location.’
Trade a bouquet of Albino Sunflowers to another player.
Find and drink a glass of True Oblivion from the London Crusades club.
There are the ‘In the Dark’ achievements, but I really just meant keeping 10/10 people alive, which could be done first time on e1.
The ‘Shutting Down World Simulation’ is completing 100 e10 scenarios, so perhaps ‘keep 10/10 survivors alive in 100 scenarios’ (edit: in a row) would be more of a challenge.
The Musem Display chronicling a player’s greatest deeds and kill count trophy board is nice. I often forget that it’s even available.
Perform 5 different emotes whilst in a Raid group using the Albion Theatre stage.
Reduce the health of all five Anima-sims to 1hp at the same time.
Kill a scenario miniboss — or whatever those big “hostile mutator subroutine activated” mobs are called — by knocking them back into the AoE of a saboteur’s bomb.
This is reminding me of a cheevo back in COD4 to frag another player by shooting a claymore mine through a wall.
Kill an enemy without any weapons equipped;
…would be very close to your suggestion both in terms of reflects and using the environment to affect mobs.