Update september 2022: here is my final version for this build:
https://underrail.info/build/?HgMPAwkDAwoZwqAAwqAAAFBRMDMqJ1BIKE8ALQDCnkMANcKjYisxFjDCh1rCmkspKsKIXT7Cs1HChW3DnMKewp3CrcKuw4Js4qe-CuK1rgXfvwWith this your laser pistol will have 97% chance to critically hit (for 600-800 at endgame without Blindsiding, hypercerebrix or SS drug) in general with Focus Stim and Hardcore chips. 100% on non insectoid organic with Body Horror. 10 Int rather than 18 dex maximizes damage, same thing with speccing CP rather than versatility, it is no problem with the Commando Belt (go hunt down the scavengers group in the caves north or the lower floor in GMS).
Skinner, ~60Q rathound leather (might buy it from Booth, just remove Gypsy.obj in data in the Underrail files to guarantee him to spawn
before the beginning of a run) and 160Q SS (just find 4 Refining Data before melting) gives +13% critical chance from Rathound. Join FD for stealth material (and the tatoo!), join Coretech (not mandatory though, and don't forget to meat Phreak BEFORE) for electronic components but Kiro at Tchort Institute is even better. Choose investigation and physics during your dialogue with Eiden to get Electroinvestigative belt for the +2% crit chance on crafted energy pistols and +15 electronics to craft plasma nades anywhere without drugs.
You can pass every skill based check in the game except psi ones and some in dialogue for dodge/evasion and mechanics saves for avoiding the fight with Iris (why would you anyway?) and 140 mercantile check at Ray's... EXCEPT if you play in march and find bespoke buckled shoes... In this case you can. You need Jacknife for some lockpicking check and Huxkey, you need White Dude (cocktail fairly often available at the Drag'n'Drop which is always in your game if you have Expedition) and Heartbreaker armor and tabis for 105 persuasion to convince Grim to do the missions solo and Sleight of Night (Drag'n'Drop again) to steal something from Ethan and/or Azif ... And that's it!
Just use knife at the beginning and abuse utilites and especially bear traps. Then you won't use anything but laser pistols and maybe phase gun a bit. The sonocaster takes care of Nagas remarkably well (with crit and amplified wave attack, You do 65X damage to them per attack at long range and for 12 AP from level 26 on!)
Psi : LTI, PTC, Statis (as usual) and for PK you use Grounding, Imprint, Electrokinesis for the CC. Last one is anything you want, PTD has its niche use maybe...
You can shoot 10 times per double accelerated turn, 11 times and 1 knife throw if it kills with the throwing glove (switch hands...) thanks to Fatal Throw.
This is a very easy and powerful build that do not require much maintenance because you'll find batteries everywhere and you just need to buy some advanced electronics repair kits (you will have the occasion to craft some too). The only downside is that it is a glass canon, but you have tons of CC with psi and utilities, fairly good initiative, good stealth with your gear and good damage distribution (one shot one dead at level ~23 and even before that sometimes, and 8, 9 and 10/11 shots per turns at level 20, 24, 26, 28... not talking about max dex with Commando Belt and Three Pointer feat shenanigans!)
You have 31% chance of PTC drawbacks effects (minimum is 30%) but it's endgame dump points, you can choose to put them in Persuasion, Mercantile, Biology (for SS drug would you decide to do DC before Expedition for example) or Mechanics (for the checks which are Tunneler repairs and a DC one to repair the gate, not really important, you won't miss content not having them, quite the contrary in fact...).
Have fun.
