Hey, I took this build to lvl 22 on hard and it's very consistent:
https://underrail.info/build/?HhAGBgUDBAYARADCoAAAAFlVAABgf0NbdQAAAMKgAAB4Jjlhwq8SK8KqwqzCh8KIwpTCgsKrwoYawpPCtnIq4p-EAeKxjAXis44C4ra1AuK2tgPit4oC378This guy is relatively good at staying alive but he's dead the moment he's stunned or gets incapacitated. Number one enemies are psi users and crossbowers with shock bolts/throwing nets. Snipers can be dangerous if you let them shoot you, but if you use temporal dilation on them it can prevent them from shooting at all. Crawlers can be dealt with caltrops and having their poison availabe is very neat. Meleers with combat gloves and sledgehammers have a chance to stun/incapacitate but they need to reach me to do anything and I just don't let them. Even if they do, I block so much mechanical (melee) damage that I'm not particularly scared.
No throwing spears because I don't really like the concept. Picked Continuum Ripple to experiment with it and I also wanted some cheap ranged AoE. Also I use a shaded visor because it makes bad positioning a bit more forgivable and movement points are at a premium without stealth. Someone talked about having free shield bash and it's really true and you get 2 free shield bashes if you used LTI that same turn. The damage on them is kind of lacking imo but the daze effect is really worth it. Do note that sometimes you need to expose weakness first because if no damage goes through then it's a waste. Having dazed, temp dilation, caltrops, taser, flashbangs, and throwing nets as options means that your enemies have a really hard time getting anywhere and you should always have opportunist. Temporal dilation in particular is very good because it's so reliable and versatile.
Currently finishing up Acid Hunters quest (should've done it way earlier but I got distracted exploring and doing literally everything else). Still haven't done expedition. Still haven't done Free Drones questline, kind of scared of SRO fight but it's probably ok.
Current gear:
-Shaded solid padding steel helmet, or preatorian lawgiver. I made a temporal manipulation headband but never used it.
-A choice between 3 riot shields - one steel shield if I ever need the extra block amount, the other two with psi beetle carapace because spamming PtC and LTI is psi hungry. In terms of vest, one is regenerative, one is galvanic, and one is biohazard. Kevlar cloth is very good when there's bullets involved, otherwise I liked having one with aluminized cloth as an option. All of them have laminated fabric ballisitic panels.
-Kevlar tabis or mutated dog tabis as an option
-Doctor's pouch because I go through many psi bosters mid combat. Alternatively, I have a utility belt and a lifting belt at hand.
-Shock steel spear although I want to upgrade soon. Jacknife in the other hand, which also comes in handy to dispel pseudo-spatial projections.
-For utility, taser, flashbangs, grenades, caltrops, throwing nets, molotovs, toxic gas grenades are all great. The last one was especially good in combination with crawler poison caltrops for the Kill the Beast final encounter. Do take attention to your psi reserves between waves, you can heal and charge battery in combat, but you can't use inhalants at any other time.
Notable hard encounters: Lurkers dog fighting ring, there's a stealthed sniper at the far end, many psi users and a crossbow. I could clear half of the Ironheads but I'm still having trouble with some areas that are very open and I get overwhelmed. Psi beetles are very deadly if they get lots of stacks going, so I have to wait for the group to kind of get all near each other and use a flashbang.
Most of my problems are mainly because I wanted to try having a playthrough without stealth to see what that was like.
Forgot to mention, Carnifex was done in one turn in one try, so that was very gratifying. I usually have to beat him in initiative.