I finally completed the challenge I attempted many times since 0.8.0.
It's AoSh on Hard (and thus Shottyman Gold).
RNG was god -- I got early (somewhere in Callisto) an ADV shotgun with +damage, 50% reload, and Chill effect, which carried me through the game, and this was the very same shotgun I took down the Summoner. I also got in Europa an ADV blue armor with faster reload time property.
And there were plenty of grenades and I used them all.
The run was still very hard, there were a number of moments when I had no medkits left. Once I had to run into the closest elevator with a smear of health from a pack of exalted kerberos. If not for Chill effect shotgun, I would have never made it.
Chill effect is OP. I got another extremely good shotgun in Io, an ADV dual with Vampiric + Reloader.
Sounds like a shottyman's dream. But Chill was still better. It's a mass slow. With very short reload time (50% + Rel2 + improved reload time from ADV armor) + fire (80% from A-mod) so fast that most oftenI could do two shots, mass Chill and then Shredder, and then a finishing shot or retreat, while enemies still stumbling.
The hardest enemies are Armored/Siege Ravagers -- there are lots of them in the late game, rockets really hurt, and it takes two-three shots (one with Shredder) to bring one down. So there was a lot of maneuvering to lure them to where I could get to them close enough, and while maneuvering there is always a chance to catch a rocket. Security bots are troublesome in Callisto, but past Valhalla Spaceport they are less numerous, so I usually just left them alone.
The most annoying are turrets. They don't wonder off; if they block the way, they have to be dealt with.
However, unlike early 0.8..., with the recent updatest there are many ways to take down a turret. Disabling with terminals if there are spare multitools. With any grenade: Frag or krak or EMP, then a single Shredder shot; or smoke/gas and then fire a few times into the fog. A couple of Shredder shots do the job, too (depending on how close you can get), but there is a risk of being fired in return. With my constant shortage of medkits, I did not dare attack rocket turrets without grenades.
My choice of the class was Marine. It's counterintuitive. But I tried many times with Tech in earlier versions for advanced modding (in 0.8.7, Tech is not very unsuitable for this challenge) and Scout which seemed like the best choice in 0.8.7. But it turns out the Marine's access to extra healing and strong defense skills like Iro, HR, and Incoming are really dominant in this challenge. Reload Dance is pretty good, too. And, of course, Shredder is designed for this.
Andizee, level 11 Marine, defeated
The Summoner against all odds.
He survived for 10256 turns.
The run time was 2h 23m 46s.
He scored 4732 points.
He liked it HARD!
He was an Angel of Shotgunnery!
CALLISTO L2 -> Callisto Mines L1
Callisto Mines L3 -> Callisto Anomaly
EUROPA L3 -> Europa Dig Zone L1
Europa Dig Zone L2 -> Tyre Outpost
Tyre Outpost - cleared
IO L4 -> Io Warehouse
Io Warehouse - cleared
BEYOND L1 -> The Arena
The Arena - cleared
Awards
Explorer Ribbon (+50)
* Visited all encountered special levels
Shottyman Gold Badge
* Complete AoSh on Hard
He killed 336 out of 402 enemies.
6 former commandos
3 former CRI soldiers
34 fiends
2 corrupted sergeants
13 former soldiers
1 summoner
1 cyberos
6 siege ravagers
8 combat drones
9 former sergeants
4 corrupted soldiers
12 CRI marines
13 cryoreavers
3 hellish commandos
4 corrupted heavys
5 cryobeross
3 former CRI sergeants
9 security drones
3 exalted reavers
3 plasma ravagers
6 exalted fiends
3 kerbeross
1 hellish sergeant
14 armored ravagers
4 security bots
8 turrets
25 archreavers
6 CRI bots
1 hellish heavy
4 corrupted commandos
20 reavers
1 former CRI grunt
1 military drone
42 fire fiends
3 exalted soldiers
19 former guards
10 former grunts
21 ravagers
5 hellish soldiers
3 former heavys
2 rocket turrets
4 toxic reavers
Traits
Hellrunner L2
Ironman L2
Reloader L2
Whizkid L1
Reload Dance
Incoming!
Shredder
Equipment
Slot #1 : ADV 12ga shotgun PA
Slot #2 : CRI plasma shotgun PBA
Slot #3 : ADV 12ga shotgun P2
Body : ADV blue armor PB
Utility : CRI backpack
Inventory
energy cell (x100)
energy cell (x63)
12ga shell (x50)
12ga shell (x48)
EMP grenade (x1)
CRI phase kit (x1)
multitool (x1)
military stimpack
large medkit
large medkit
large medkit