Oh yea, I forgot in Underrail u can like, uh uh, lay traps. Sometimes. Then, with the single PC you have in party like... point a weapon and click. Uh uh. Once per turn. Maybe twice, uh ah. Maybe use a skill every now and then, uh uh. So kewl. So skill. So cummplex.
Very lame, mate.
Fallout 2 has several potent builds, but they differ only in means of offense.
Sniper build. Max PER, max AG, optionally max LUCK (not necessary since eyeshot gives you +60% to crit chance, I played snipers with 1 LUCK). The goal is to shoot as much as possible per turn and deal a lot of damage per crit while staying as far as possible from bad guys.
Full-auto build. Max AG and LUCK, ignore aimed shots. The goal is to burst as much as possible while critting with every burst. Takes longer to come online but is disgustingly OP once it does. You'll need high STR for heavy weapons, though; SMGs become very frustrating later in the game.
Close-encounter builds, melee or unarmed are very similar so they don't differ much. Once again, max AG, max STR and have better END. Melee builds are inferior to ranged ones since you need to get close to enemies and you will take more damage.
There's no difference in means of defense. All those builds will come up to PA with which you become very tanky, there's no shields and dodging is largely irrelevant. There's no difference in terms of mobility: you always want to have 10 AG and pick up those Bonus Moves and Action Boys. Stealth is available to all those builds and makes them even more powerful.
Underrail, in turn, has build varieties for every weapon class, and several paths within each of that classes (for example, full-crit AR or base damage AR). Underrail has differences in means of defense (dodging, tanking, shields, PSI-defenses, or even smart planning). Underrail has different approaches to mobility: tanky build with 0 MP or highly mobile builds. If anything, Underrail introduces more variety to offense, but also affects defense and mobility. There's no glass cannon builds in Fallout, but plenty of them in Underrail.
Some things are constant in Fallout. You always want to have 10 AG and maximum of perks augmenting it. You always want to have the best armor available. You can always invest in stealth to be even more unstoppable. The choice of guns is not important as well. Full-auto build will always come from SMGs to ARs to miniguns or Bozar. Sniper build will come from Hunting rifle to Sniper Rifle to Gauss, Pulse or Turboplasma.
Ironically, Sonora is the first game using Fallout engine that makes difference between pistol or rifle using sniper builds and SMG or AR using full-auto builds.