Races
AoA: Thalore is good because Nature's Pride helps buy time between Vaporous Step and Solidify Air cooldowns and Wrath of the Woods is great with resist all stacking. Ogre's Grizzly Constitution is ridiculous with Medical Injectors but otherwise has no synergy. No other races have any notable synergy so the standard ranking applies.
EoR: Yeti and Orc are both alright. Don't go Whitehoof since you don't move often without a speed boost and you want an Infusion late.
Stats
Early get just enough Dex, Wil, and Cun for talent unlocks, then Str > Cun > Wil > Dex. Try not to get Dex above 28 or so or you risk not having enough points to max Wil.
Category points
AoA: Inscription slot -> Dread -> Inscription slot -> Nightmare
EoR: Inscription slot -> Dread -> Avoidance or Nightmare
Inscriptions
Early you'll want two Medical Injectors and two Steam Generators because it's expensive to keep up both Molten Iron Blood and Mechanical Arms. Later go down to one Steam Generator. Good Inscriptions for the remaining slots are Movement Infusion for reload and kiting, Heroism Infusion for not dying and boosting damage and powers for status application, Phase Door Rune and Wild Infusion for resistance stacking, and Primal Infusion for affinity stacking.
Prodigies
Always take Pain Enhancement System at level 30 because you want to do a lot of weapon damage with non-Str weapons. For your other slot, Superpower is optimal because it's like PES but worse, which is still better than everything else. If you really don't like Superpower for whatever reason, you can go Dex over Wil and take Vital Shot but it's definitely not recommended. If you want a defensive prodigy, Draconic Body should be the best one since you don't really need Spine of the World or Draconic Will. No other prodigy is worth mentioning on this class, seriously just take PES and Superpower.
Tinkers
Belt: Fungal Web for sustained healing. Backup: Thunder Grenade for AoE stun.
Body: Ablative Armour for crit reduction and armour, Backup: Spike Attachment for armour, Second Skin for status resistances, or Crystal Plating for damage.
Cloak: Grounding Strap for stun resistance. Backup: doesn't matter they there aren't any other good options.
Feet: Rocket Boots for movement. Backup: Moss Tread for kiting melee enemies.
Hands: Fatal Attractor for taunt summon. Backup: any other summon or Itching Powder.
Head: Headlamp for accuracy or Focus Lens for sight radius.
Lite: White Light Emitter to boost damage of Crystal Edge if you're willing to spend the generic point. Otherwise don't bother with this slot.
Ammo: Saw Shell for raw damage, Explosive Shell for AoE damage, Hook Shell for mobility, or Corrosive Shell for armour reduction.
Weapon-steamgun: Acid Groove for damage and armour reduction. Backup: Crystal Edge for damage and crit mult, Winterchill edge for slow, or Viral Injector for stat reduction. Steamguns sadly do not benefit from Razor Edge or Silver Filigree.
Weapon-mindstar: Crystal Edge for damage and crit mult, Silver Filigree for demons, undead, and horrors. Backup: Winterchill Edge for slow, Thunderclap Coating for knockback, or Viral Injector for stat reduction.
Class Categories
Psytech Gunnery: 5/1/1/0 early and core, more points in Blunt Shot and 1/5 Vacuum Shot luxury.
Psyshot active does lots of damage but being mind damage is often a downside unless you get Nexus of the Way or other big mind damage boosters. Use this on cooldown because it gives you a net gain of psi. Note that your mindstar hits apply melee procs.
Boiling shot is great early with Condensate, float points in early but make sure you can refund. It's really expensive in terms of steam and psi so don't use this at all in long fights unless you need the AoE.
Blunt Shot is an AoE stun and AoE stuns are good. I find putting more than 1/5 point in it unnecessary because you rarely care if someone is stunned for 4 turns or 8 because of the rest of your talents, but it is a good sink for excess points. Stun tests steampower against physical save.
Vacuum Shot is pointless aside from the damage, but it does pretty nice damage with a low cooldown and cost. Usually not worth the psi and steam though.
Thoughts of Iron: 3/1/3/1 early, 5/1/3/1 core, 5/5 Mind Injection luxury
Molten Iron Blood is your most important defensive talent, keep it on once you have the steam to. This gives 23% resist all which stacks very nicely with Thick Skin, Steam Powered Helm, Pain Suppression Salve, Wrath of the Woods, and many other sources of resist all.
Mind Drones is okay if you’re disarmed or something and don't need the psi. Rarely worth a turn otherwise since the talent fail chance is so low, even at 5/5.
Psionic Mirror is a great cleanse that sends conditions to enemies. Sometimes it’s best to wait for them to use more debuffs before using this talent, like waiting for Burning Hex after being hit by Pacification Hex.
Mind Injection is great. You don’t care about the modifiers as much early but it’s worth maxing later.
Mechstar: 1/1/1/0 early, 3/3/1/0 core, everything but Steamstar luxury
Metalstar isn’t flashy but it gets enemies out of your face pretty well. It doesn’t work well against enemies with good physical save though. 3/5 is a good radius breakpoint. Both statuses test steampower against physical save.
Bloodstar is a bit of damage and healing. Not much to say here but it’s better than it looks and it really shines against groups of enemies. 3/5 is a good duration breakpoint. I'm pretty sure this cannot be saved against.
Steamstar is good for steam early, decent for damage late. No reason to get more than 1/5 in it.
Deathstar would be good if your shoot talents were good, which they aren’t. It’s not bad but not essential either.
Gestalt: 1/1/0/0 early and core, everything luxury (but Gestalt and Forced Gestalt are probably best)
Gestalt is basically required to keep your psi up, and it gives some mindpower and steampower as a nice bonus. 3/5 usually keeps you from running out of psi, but you don't really need it until late if you aren't wasteful.
Improved Gestalt gives a weak shield every few turns. It’s not great but it’s free so can’t really complain. Note that this overwrites other damage shields for some reason so avoid Shielding Runes with this class.
Instant Channeling turns your steam into psi and a shield, and funny enough the psi is usually more important than the shield. However, if you invest heavily in both this and Improved Gestalt, you get a very large shield (855 damage at 5/5 both talents and 100 mindpower) on a low cooldown.
Forced Gestalt is essential for getting statuses to stick on enemies with very high saves, like Elandar and Argoniel. As such, this talent is much better in AoA than EoR, and I would highly recommend maxing it before the final battle in AoA in order to get Inner Demons to stick.
Action at a Distance: 1/2/0/0 early and core, 4/5 Solidify Air and maybe Superconduction luxury
Condensate enables Boiling Shot, which is a combo that will carry you through the early game. It also enables Blunt Shot against stun resistant enemies, provided you can beat their physical save with both steampower and mindpower since this talent tests mindpower and Blunt Shot tests steampower against physical save.
Solidify Air is this class’s Stone Wall. Use to give yourself some breathing room or to isolate a single target. 2/5 is really good for 6 turns, and the next two points add one turn each so they're worth taking late.
Superconduction reduces mental save by a decent amount, but you have to beat physical save to even apply it so it won't save you if your mindpower is really bad.
Negative Biofeedback sucks and even if it didn’t, you don’t have the psi to use it.
Psionic Fog: 1/1/0/0 early and core, Psionic Fog luxury and Uncertainty Principle luxury.
Vaporous Step is an instant teleport therefore it is amazing. Only reason to precast it is to play around brainlock since you aren't in it for the damage, so don't bother. This applies the wet debuff in an area around where you move from so comboing it with Blunt Shot or Boiling Shot is good.
Inhale Vapors adds a heal to Vaporous Step. It’s fine at 1/5.
Psionic Fog is pretty much an AoE DoT version of Superconduction with a weaker debuff, making it usually better overall.
Uncertainty Principle would be great if not dependent on using Psionic Fog. It's not the worst talent ever but it really isn't that good either.
Avoidance (locked): 5/0/0/0 core, 4/5 Cloak Gesture, 3/5 Embedded Restoration Systems, and maybe Cloaking Device luxury
Automated Cloak Tessellation is great because the flat damage reduction applies after damage resistances.
Cloak Gesture is good if used with Arcane Eye or similar. Could probably help make Lucid Shot actually work.
Embedded Restoration Systems is alright if using Cloak Gesture, but it may cost too much steam for too little benefit.
I haven't tried Cloaking Device since stealth is unreliable but could potentially be worth some spare points.
Nightmare (locked): 1/5/0/0 core, Waking Nightmare and Nightmare luxury
Nightmare is only good for prepping Inner Demons and Waking Nightmare and for buying time to escape.
Inner Demons slays bosses. It's great if you have the mindpower to get it to stick, which is why Forced Gestalt is so good late.
Waking Nightmare is unreliable but at high mindpower and talent levels it procs rather often.
Night Terror doesn’t do much since any significant damage will wake up your target immediately.
Dread (locked): 3/1/0/0 early, 5/1/1/2 core, Mechanical Arms, Lucid Shot, and No Hope luxury
Mechanical Arms does little damage until late but it makes you take less damage and also enables Lucid Shot. It makes you a proc machine though because it applies all melee procs. The harassed debuff counts as a fear for Lucid Shot.
Lucid Shot supposedly makes enemies kill each other, but I've never actually seen it happen. Maybe it would work with Cloak Gesture but I never tried it. At least the damage is very high and the cost is low enough that this talent is worth using even without the debuff.
Psy Worm isn’t good because it does low damage and Gestalt and Instant Channeling are better for psi management
No Hope is great for keeping you alive and enabling Lucid Shot, but good luck getting it to stick on high difficulties. Forced Gestalt is huge here for the same reason it's so great with Inner Demons. Beware the massive psi cost. This counts as a fear for Lucid Shot, so don't Lucid Shot people you use No Hope on because No Hope is the better debuff.
Generic Categories
Physics: 4/2/1/0 for Crystal Edge and Fatal Attractor, more for Steam Powered Armour if playing EoR, 2/5 Electricity if you want White Light Emitter
Chemistry: 5/1/2/5 for Unstoppable Force Salve and Ablative Armour, more for Life Support Vest, 2/5 Chemistry if you want Itching Powder
In EoR, take 4/5 Theraputics instead if you get Brass Goggles.
Steam Power is great, it most notably boosts Automated Cloak Tessellation and the chance for Blunt Shot and Metalstar to apply statuses.
Engineering: 0/0/0/0 core, Last Engineer Standing luxury
Emergency Steam Purge owns early but scales poorly. Make sure you can refund fully if you use it early.
Innovation sucks.
Supercharge Tinkers is worse than Steam Power, and what’s even going to crit?
Last Engineer Standing gives nice miscellaneous boosts, most notably the crit damage reduction. You probably need this if going Vital Shot.
Combat Training: 5/1/0/0/0 core, more in Armour Training and Combat Accuracy as needed
Mindstar Mastery: 5/0/0/0 core because Psiblades boost the damage without having the sustain on. Don't turn on the sustain though.
Blacksmith (locked): never unlock, Craftsman’s Eye would be luxury if it wasn’t locked.
Survival (locked): never unlock unless you really know what you’re doing, Charm Mastery would be core for experienced players if it wasn’t locked.
EoR Yeti Tissue Rewards
Change the order as you see fit
1) Psiblades (5/0/0/0)
2) Conditioning (1/5/0/0)
3) Dream Walk
4) Chant of Fortress
Gameplay
Keep high resist all up at all times with items, Pain Suppression Salve, Wild Infusion, Phase Door Rune, Wrath of the Woods, etc. When you hit or come close to the resistance cap, you will heal for more damage than you take with affinity from Salves. Fun ways to abuse this are to use Fiery Salve when burned and Water Salve when diseased. Space out your uses of Solidify Air, Vaporous Step, and other mobility talents and items (and Stone Wall if you get Wrap of Stone) to keep enemies from attacking you for as long as possible. Be mindful of your psi, since No Hope and Nightmare talents burn your psi pool very quickly. Combo Vaporous Step with Blunt Shot then Boiling Shot for an AoE disable and damage. Hold onto extra quivers for a immediate full reload, and use Movement Infusion, Rocket Boots, or similar to quickly reload ammo.
Itemization
Items that are universally good are all good as always. Tarrasca is already one of the best possible armours but it's even better on Psyshot since it stacks with your resist all and your affinities benefit greatly from this combo. Eternity's Counter is really good on offense mode with Tarassca or defense mode otherwise, though sadly I had to use a Perfect Strike pick in that slot instead because of accuracy issues in High Peak
. Thoughtcaster is a ridiculously good artifact steamgun, and Nexus of the Way is the ideal Mindstar because of the summon. Resist all is your number one priority stat, so items like Steam Powered Helm are better than usual. You need 50% stun resistance from items since Grounding Strap gives you the other 50%. Otherwise, good stats to prioritize are armour, maximum life, healing mod, physical and mind damage, accuracy (as needed), mindpower, physical crit chance, crit mod, and melee status procs, especially gloom, amnesia, and slow.
).