UPDATE - https://steamcommunity.com/sharedfiles/filedetails/?id=1662842028
I started to update my guide on steam with expedition, still WIP but there is essential information.I managed to beat the game with a very similar build on hard few mouth ago, and everything went really smoothly.
https://underrail.com/forums/index.php?topic=3881.0Depot A was piece of cake, foundry beasts was like a walk in the park, nevil and I against an army of bots was done in one go, arena was fairly easy (though with a lot of reload for the final encounter... But once I got the initiative, it was done in one go), DC itself was easy mushroom or army of bots could'nt wistand the powerfull acid entanglment combo + powerfull special bolt in the face.
Every fight was easy... Every but one. The final boss was a pain in the ass (mainly because that big blob bastard could not be snared) and that's the reason why I think this build was not able to finish the game on dominating, even if I'm quite sure it will bring me, even on dominating, in front of the final boss.
And then, come the expedition... And new ideas, and a new updated build i'm first trying on hard, and I hope I'll beat dominating with it.
http://underrail.info.tm/build/?HgMIBwMOAwgjN8KgAADCoGQASwBGWl9fRloALQA3AAAtKxrCowFhFiLCkcKAL0wwS2oqJyTCpCbioaQF4qiICt-_The whole thing is built around deadly snare + acidic entanglment from acid pistol. Giving access to critical hits with special bolts.
And to do the trick, we'll use pneumatic AA cyclon crossbow + acid pistol plus advanced catalyzing belt
But this only comes at level 14, and it has to be potent enough before hand. And as a matter of fact, it is.
I'll explain every choices made, and how to play the build. But trust me, you'll have a lot of fun playing that glass canon build.
Feat choices :
-Versatility : it's a core feat, used to be able to use both crossbow and acid pistol. Plus it will help early game against rathound, if you come across a knife.
-sure step : it's really important to pull the acid puddle + caltrops combo. With good poisoned caltrops, you can do a ton of damage on multiples target, regroup them thanks to AP reduction and kite them avoiding any melee attackers.
Plus it will cheese a lot depot A, Omega and some early fights. An overall good choice.
-aimed shot : Even if it seems obvious, maybe it's not needed. However, it's nice to have a powerfull attack on a solo target. It's nearly quality of life because most of the time you could "waste" a fragnade instead. Won't be that usefull early game, but late game will prove more usefull once you'll get a strong AA crossbow.
-marksman : well... You'll use a lot of special bolts, so... It's a no brainer. Plus, it will replace strafe feat, once you'll get the specialization for it.
-grenadier : here the big change. At first, one might think it's stupid to have grenadier since all your slots will be used by special bolts. But with the addition of temporal manipulation and a grenade every turn, well it's really potent.
Anyway, you'll have to prepare to every fight by choosing : the most suited special bolt, the most suited grenade and the most suited utility grenade (caltrops, flashbang, emp). And thanks to Quickpocket we'll get later, even with catalyzing belt, easy to get enough slots.
-cooked shot : well... Great feat. You'll be able to ignore targets evasion. You'll do AOE damage and snares. You'll multiply the chance to get acidic entanglement. You'll be able to spread acid over caltrops out of combat.
-bowyer : +35% critical damage on crossbow is a lot.
-Quick pockets : Not needed early game because you'll be using a utility belt. But at one point, you'll use an advanced catalazing belt, and you'll then need that third slot.
-Deadly Snare : everything revolve around this feat.
Once you'll have this, you'll be Deadly.
-Quick tinkering : almost everyone know it's a great feat. And if this build was not that dire on feats, i'll take it earlier.
It's both a defensive feat that allow road blocks especially combined with force field or electronic imprint.
And offensive one if used with a powerful mine you drop in front of targets, run, and then explode thanks to a grenade.
-Critical power : Well, I'll rename it Deadlier Snare.
-Elemental bolts : Let's rename it... Even Deadlier Snare.
-Premeditation : Will give a free action every five turn. Great utility to get a stun with electrokinesis, or a life saving forcefield.
-Pack Rathound : If I could, I'll get this earlier. 3 Str character are a pain in the ass for inventory management. This will help, and you'll need it to get to DC. However, it's quality of life and i'm sure one can do without it. But you'll get to carry less loot and less traps and grenades.
-Nimble : early game, you'll use the Rathound king armor suit, so armor penalty of 0. but you'll be happy to still have armor penalty of 0 with a Phantom Dancer armor or a regenerative tactical vest. But this will only be needed end game.
-Scrutinous : +7 crit chance, with good crit NVG you can reach 30% crit chance with your acid pistol. Very potent with cooked shot if you get an entanglement.
And why I'm not taking +2 perception one might ask... Well I'm not sure. The main issue is that perception do not bring extra damage with special bolts (only mechanical damages are affected by it), so the effect is not that great. It will bring damage on the acid pistol though, but I prefer the crit chance somewhat.
-Opportunist : Extra 30% damage on snared targets, for really really tough targets.