Well, aside the obvious, this game needs a hintbook I'd say.

Sure, you can level up to 20 the whole family, but actualy exp or gold (ye, its some ore, I dun care, looks like gold, works like gold) come scarce, so that's not attractive option.

Also, when the characters get unlocked seems to depend on dungeon reached, as they come through cutscenes (ery long, pace-braking cutscenes), and you can run out of 'em.

So:

Dungeon 1, part 1 of 3:

You start with Swordwielding Guy. He is melee. Don't get fond of stuff/abilities you find, they will be stripped from you when you die/pass the dungeon. Still, this character has moderate melee AoE, and is closest to a tank - a tank with very limited HP, no healing source, and hoards of archers waiting in the dungeon - still. The saving grace here is the basic ability on rightclick, which is ranged.
Evade is only useful to any melee character when facing trolls - and when you face an elite horde of five troll, your melee guy will be burried.

Almost immediately you also get Archer Girl. She is bloody slow attacker, but range has advantage if you have space to manuver. Evade-rolls realy come useful for this.
Note: while it is possible to hit enemies out of screen, that might result you not gaining exp, rage and stuff from them.

A late while arrives Knife Boy. This is your combo-reling character, meaning it gets better when hits enemies a bunch of times, and constantly has to keep hitting things. Vases are ok to hit. the purple exploding plants are your death.
Also, the spike-traps are barely noticable, very bad news to any character, but especialy melee ones, extremly if magnet totems are present too.

Now, the boss here a HORDE of spiders (kill the big ones first, move when the boss will fall down), thus you'll need a melee character with substantial amount of luck for gear and HP-potion finding.
Or maybe soul-gem finding, as you'll "free" a vendor, which sells stuff for soul-gems, which until that point can be used to unlock chests, but that's entirely not worthy use of them. Spend them at the vendor instead, and buy potions to refill your health bar before anything else!

If you could not pass this portion, level up the other characters to skill level 4 to gain family bonuses.

Dungeon 1, part 2 of 3:

This is the same old story, with probably 2-3 new monsters, like you'd realy notice that after the 20th try.
The dungeon is hugh, especialy at this stage, and is choke full of ranged units.
For everyone's fortune the boss is only 2 minotaur, or more like goatmen (the cutscenes refer them as goblins, but don't mind that), so the Archer Girl is perfect choice here. Watch out, one of the goatmen attacks AoE, like a troll.

You get during this phase Martial Arts Guy, but he is very pathetic in this environment. Still worth to level him to slvl 4 for the family bonus.

Dungeon 1, part 3 of 3:

A new character is unlocked, the fire-mage-girl. She is the first decent character, and perfect for the local boss, who plays Bullett Hell.
The Fire Mage Girl shoots rapidly, and her first ability is a shield that absorbs damae. Any amount, up to 3 hits, which is the maximum possible investment - I assume for any skill.

New ~enemy is a spawning-gate.

New feature is the "chase the creature" - I have no idea what happens if you succeed, as the sub-dungeon (a teleport brings you there and back) is filled with elite hords.

Book of Rea max levels

Dungeon 2, part 1 of 3:

Here "the last playable character" is unlocked. Well, there's another playable character according to the siluettes.
This despite melee COULD be interresting, but the charging enemies are the death of it. Otherwise it uses a hammer, which creates a wall of steel if swinged rapidly, but the first swing takes ages to be done.
It specialyity is rage, so it doesn't give much to the family.

Let's roll through which characters has what family-bonuses:
Mark gives evade. and boosts high hit combos. Pretty meh.
Kevn gives critical damage. That's ok, but comes very late.
John prevents getting killed, and GIVES REGENERATION. So this is the character to invest into ASAP.
Linda (the archer girl) stuns enemies, and incrises speed when you are not attacking. That's ok, the later especialy elevating the fire mage girl.
Lucy, the fire mage girl gives another gemstone. That's pretty much it, but as things stand, she should be your primaly used character, so duh.

The traps (spikes, and instead of magnet shrines now sandpits (which are magnet shrines that hurt yo) are more visible.
The hoards are also many.

There is some good news: this area can give you a good amount of gold (morv), like 1-2K.
Talking about "morv" (gold): this was when I've noticed Book of Rea has a buff for this too, so this should have been delt with way before, suffocating early game even more.
Currently what I'd actualy need is HP and DMG, but oh no, we can't have that, we need to waste time and effort on gaining the proper amount of most basic resources!

Oh, by the way, the game says F you and FORCES you to switch characters now and again giving the "corruption fatigue", which lowers their max. HP.

You should play this stage long enough, because a side-quest character will be unlocked. The sidequest is some old dude and some young boy is on a cart, and want to go to a telescope, then they want to collect garbage tio fix the telescope. After that you find the cart again, this time with the youngster's blood on it. After that the old man shows up at your home, and from that appears every time at the merchant, and gives you a free gemstone.

Managed to find another teleport here for chicken-chase.
This is LITERALY a chase, you just have to follow the easiest path of footsteps of the chicken. All will eventualy lead to the chicken I assume, thanks to procedural generation.
At the end of the road will be a FORCE FIELD, behind that awaits the chicken and just gives you an egg without a fight.
At this point you can backtrack and deal with the enemies in this sub-dungeon for gemstones and exp. Given you have a forefield to draw back as necessary, it is a pretty safe bet.

After this dungeon (I mean by beating its boss) you will be forced to visit a new area called "Forest". This means you'll be cut away frmo training in areas and all.

The Forest is bugged as heck. Also, give no resources aside some healing potions, and those are way too scarce too.
So, what you are supposed to do is to run from the Big Evil Boss to some barrier(s). The barrier should disappear when the boss get close - 50% of the time it does not.
Then you rrive to an arena, which supposed to close behind you. At least with a 10% chance it closes before you, rendering you unable to pick up the key items (3 gemstones by stops).
In theory you should avoid the blobs spawning on the ground while defeating monsters until one of 'em drops a gemstone, which you have to put into the central pillar. This clears the currently running monsters and initiates the next wave.
Note, that the monsters CAN run out, AND they come in waves, where the next wave iis initiated by destroying the last monster out. This later part might only be true after a while, the earlier waves might arrive earlier is my gutt feeling.
It is beneficial to preserve the chests (again they only have healing potions) and clear the first or second wave entirely, then heal up.
There are 3 areana battles, the last is the bossfight, with somewhat different rules, like the gemstones do clear the current monsters, but the gemstones after a certain number of use will stop dropping. You also don't have to wait for the gems, your goal is to defeat the boss itself.

Dungeon 2, part 2 of 3:

Here you'll find the playable unplayable character, lol. So, she doesn't count in the achievements, like every "playable character" (not simply Bergson, what would solve this issue) defeat the same boss.
Do it on the very first dungeon's spider-boss. the dungeon is relatively small, and at this point you'll get a ton of family-traits.
Tips: with hammer-guy run in, and start swinging. Determine direction of swings by the mouse to eliminate the extra spiders. This guy has a ton of HP and armor, so it's ok.
Sword-man and archer-girl should be high-level anyway, so should done.
For martial-arts guy the trick is, to only have enemies in front of it. Roll away if this is not true. Do hit&run this way on mobs.
For the defeat boss w/o gettinig damaged the firemage-girl is perfect given she can suffer 3 hits before getting damaged! Also use the decoy, especialy to get rid of the extra spiders!

The new character has a mid.range, forward 90 degree AoE-attack as primary attack. Pritty nifty. Ranged units still are problem, but otherwise very though.
Watch out though, insteod of moving forward by each attack this characer steps backwards.
A worthy sidenote is, that in dungeon 1/2 with her managed to collect 10 divine item (do not activate your R-button items to get an extra divine slot for this) Sure, this included a ton of lucky spawns, and gemstones found, and adequate items at the trader, but still.

The boss of D2/2 is pretty pathetic if you have some AoE ranged ability. I'm almost lvl 20 with the father, he was a perfect pick for this fight.

Ben's Machine's parts are in City 2, part 2. Where you encounter slaves to be rescued. They do NOT appear in part 3, and I doubt they appear in part 1.

The "challenge rooms" seem to be the ones where wave of enemies spawn at you, but I'm not sure. These rooms seem to be quit regular in City 2 part 3.

For the No More Secret achievement you need to kill a bunch of enemies "in combo" on seals painted on the ground in the first dungeons.

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Some late(er) szage character analysis:

John:
Shield of Thorns: terrible skill, because the enemy is many, this does not allow you to move or attack.
Heaven's Strike: being the only ranged attack for the character, and it is pretty AoE, it is in high demand.
Guardian Rage: I never got into GR-skills
Aged Vigor: being a melee character, you'll need this
Shield slam: it is an ok skill. Not that great, so 1 point is mostly enough.
Grit&Might: I never needed more stamina than without this
Heaven's Grace: convenient, and potentialy life-saver when fighting big hordes, or elite units.
No quarter: useful. Nothing special, but useful.
Shield dash: with so many tactical skills, I skipped this
Shield bashing: if you are into the shield, pick it. Otherwise skip it.
Last stand: it's a "you survived death" skill. Of course you want it!
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Final words: pretty mediocre character, but you NEED this on clvl 20 for regeneration to the whole family

Lucy:
Cyclone: it's absolutely devastating on runes, pretty useless otherwise. Still might worth 1 point for its chained skill.
Protective ward: this skill simply makes this character the best in the entire game.
Decoy: another bread&butter skill. Upgrade when you feel the HP/duration becomes lacking.
Guardian rage: this character actualy welcomes this skill, as otherwise you can't attack while moving, and the firebreath-effect is convenient util you primary attack becomes stronger.
Incindenary Shot: it helps with the mobs. No need to overdo it though, 1-2point.
Auxiliary embers: now we are talking crowd-control.
Beam amplify: it helps Guardian Rage for its range. If you use GR a lot, you should invest more than a single point for damage, otherwise you can leave it like that.
Rapid combustion: you realy don't want anything in melee range, so you don't need this.
Dust Storm: this is what's behind Cyclone. It's a buff appearing at critical hits. Any buff is more than a no-buff, so ye, after you tried everything, why not.
Atar's wrath: I did not unlock this, so no idea where those meteors will fall.
Mage's will: your respawn-skill.
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Final words: strong ranged character. Easy to use.

Linda:
Harmonize: Especialy early game you'll need to invest here a couple of points, because you'll be backing a lot during attacks.
Explosive crescando: oh yeah, this is an upgraded, though ~single target attack of John's Heaven's Garce. The upgrade is, you can choose where to hit, and it hiots behind walls too!
Inner rythm: makes you pretty stronger, though the there is an unmentioned upper limit of 6 stacking.
Guardian rage: being an early character, you might try this. It doesn't alter what you do otherwise, just makes you do it faster.
Absolute focus: GR buff skill
Harmonic slam: a useful secondary attack/crowd control. It basicaly saves you from being linched.
Rain of arrows: GR buff
Lento to grave: it helps you deal with the units stunned by Harmonic slam, or slowed by Lentando Charm. Or a good passive buff for multiplayer mode.
Lentando Charm: helps you in situations when monsters get in melee range.
Deft hands: makes you shoot fatser. Who doesn't want that?
Replenishing focus: heals you a bit when entering GR-mode. Sounds pretty useless once you unlock John's regeneration, but who knows.
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This is a very early ranged character, and helps you progress when Corruption Fatigue hits Lucy. But if you hit clvl 20, try to develop the other family members too elevating everyone to clvl 20, she isn't THAT good to not do that.

Apan:
Asva Pulse: sure, by time, this can be an ok investment. But there are better skills.
Asva Thunderclap: a stunning secondary attack. Of course!
GR: a defensive guardian rage. Sonds worse than the others.
Asva curse: with constant Thunderclap yes, you want this!
Magic Glyph: this is a pretty horrid, but existing third attack for the character. It has a very large radius, but you can't move during it. If the enemy is slow, or most its units are damaged already, might worth to try, but I'm no fan of it.
Charged Asva Thunderclap: if you don't just hit with thunderclap, but find some time to aim with it. Not likely, but whatever.
Restorative transmutation: you'll get damaged, so you'll consume life-globes, so ye, pick this. You should know though these do no accumlate, and they are not like Lucy's shields, these only buffer a set amount of damage (20 dmg to be precise). Not the worst skill in existence, but could be better.
Healing Glyph: adds a healing to Magic Glyph. Not convincing.
Rage fill energy: your ability timers reset or something when entering GR.
Confounding Grace: sure, obelisks are good, but I could have used some buff reaching to this level buffing exp-shrines. Whatever.
Second life: the usual respawn-skill.
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Final words: what makes this character interresting is the not-melee AoE primary attack. Otherwise the skills are pretty mediorcre. Where it actualy helps is giving more HP-potions (life globes) to the melee characters who need it.

Joey (the hammer guy):
Forceful evasion: horrible skill. There's no stun on it, and only effects where you land, not anyone you meet.
Vengeance: you get hurt, the next attack of yours will do a ton of dmg. Ok.
GR: it's just me, or walking into enemies doesn't sound a good idea?
Smite: a useful, mid-range secondary attack.
Iron will: damage buff if you want to stay, speed buff if you want to run. Ok.
Whirlwind: you know this from Diablo 2. Here you don't need a horrendous amount of mana to use it though.
Rage globe: helps you to enter GR-mode more often. I don't see the point, but go ahead.
Divine smite: again a skill where for time your secondary attack gets additional properties. When you are out of other ideas, pick this.
The more the merrier: even more damage. Ok.
Nimble wind: you can control movement during whilwind. Sure, I think.
Unstoppable force: now we are talking. Anyone melee hits you gets stunned.
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Final words: This is your damage-guy. I could have used some ranged unit control somewhere, and until you start swinging that hammer it takes time, but the character is not that vulnerable, so it can work out on the long range, for a while.

Mark:
Scouring whip: a secondary attack, which stons AoE. Yes, you want this.
Atman's barrier: eventualy you should develop it,it practicaly makes your HP last longer. Invest as needed, but don't meks this the priority.
GR: who knows.
Assault Blitz: you definitely want this, 2 or even 3 point. Though 2 is probably enough.
Zen: extra ctirical hit. CH will be the focus of thi character. I think the buff if per unit on the counter, and being a melee character you can reach pretty high number here (Ive had up to 80, what'd mean a 40% plus, but an average 20 still means a 10% bonus, and we're talking about a single point investment here.
Swirling staff: it's again one of those bad aura type third attack types. This only helps if the mob is only melee, but they'll be pushed back. I'd just keep using the whip though.
Spirit surge: can help, but I wouldn't rely on it.
Purge: even more critical hits to enemis with debuffs on them. So yes, use that whip.
Vault: if you can somehow activate it (controller issues can be present at least with keyboard), might worth it.
Restorative rage: again, GR heals you. Still sounds lame.
Atman's Grace: we're into this Atman's stuff, eh? Well, this at least buffs you for a good portion, so 1 point in Spirit Surge, grab this.
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Final Words: definitely at least mdeium difficulty character, but gives a different playing style to the mix, thus I approve. Also seems to have good luck finding Secrets and such, unlike the hammer-guy who notoriously got nothing at me.

In 2/2 I assume freed the "rune melder". His function is that at the merchat's place refill your runes.
Also the same area I assume freed the gambler too. It gives you for a gemstone a) a healing potion b) some gold c) a random item. So if it is the last section before the boss blast your gems for the hope of some permanent buffs (divine items). Oh, the consumable divine items work like this: they are either oneshot items, or permanent items. Read the description to know which. Permanent ones give permanent buffs but disappear the same as the oneshot ones.
Now back to the rune-melder: you shall know that it is not simply an additional NPC, but replaces the shopkeeper NPC when it appears. So he's pretty bad. You also find runes like no tomorrow, so he is pretty useless either way.

Just on the record, the 3rd - which is the last - city/area is very underwhelming. Sure, it is a very disturbing place, but has barely any enemies in it, with hardly any suprising trick, so it is a cakewalk, and a short one too, only haveing 2 sub-areas, and those having 2 and 3 blocks respectively.

At least the final fight happens in a separate realm of this three, making a ~4th dungeon/city, so you can safely gather achievements in the other three, but that's it.

Doing the Last Fight doesn't mean you can't progress collective achievements in the same game. Winning the game simply means you unlocked all areas.
That's a rleief.

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Family trial mode:

This is a true rogue-like mode with risk vs reward elements.

You get a randomised dungeon, on "normal" difficulty 13 levels. You have to pass all levels with a single character.

All skills are unlocked for your chosen character at slvl1. Family traits do not play.

You still get "gold" (morv). You can spend it in shops to get activateable items, or to get healed.

You still get gemstones. You can gamble at shops with these. Shops also offer to upgrade your divine items - by spending a load of gemstones, so stop gambling!!!

At each levelup you get "talent points". This means 1 point you can spend on a tabloid of 3 choice of either your character's skill getting improved, or an ability you'd otherwise get as a rune, but now it is a skill, so it is unlimited. Of course being roguleike you loose this progress if your character is defeated.

You still get those runes on the floor you can unlock by killing a large amount of enemies on/near it. This time it doesn't give runes, it gives a divine item, so it's likely a permanent boost, like the "talents".

lvl 4, lvl 7, lvl 11 are shops, 8 and 13 is a boss.

Hard difficulty has 17 more levels, I assume 1 more boss, 1 more shop, 2 more normal level. The levels are bigger, with more monsters. This means more exp (I feel more exp per monster anyway).

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What to choose for the trials:
- never pick anything that slows you down, only if you also could pick up something that incrises walk/run speed!
- never take the thing witch makes you constantly loose HP!
- do not pick more then one thing that regenerates your HP, but pick that one. When needed, just stand in a corner until full HP.
- if you can seriously accumlate dodge., do it.
- for the kickstarter-character (mid-range staff lady) pick poison damage on normal attack (and any DOT along it), it is magnificently strong.

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Oh for F sake!
So, I've been hunting the last souvenirs, and that stupid planks (#10) never shown up.
Turns out there's an encounter where John is helping some refugees. This is actualy not a flavour-encounter! Nothing indicates the importance, but it is actualy A QUEST. On the same dungeon-level you'll find another encounter, which I assumed was for material for the dog's house, placing some wood on the floor. It is not. It is the second part of the quest for the planks (#10 souvenir)! So after gaining th woods, go back to the broken wagon/refugees/John encounter, and give them the wood!

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Ok, so managed to finish Family Trials 2 times.
- Lucy has DPS, so of course after a couple of tries I've done it. The lack ov maouverability is a darn though.
- Apan: well, she has some range, crowd control, so if you actualy manage to do damage, she can pass the bosses too.
- John barely has any skill to chjoose from, and he also suffers from the secondary attacks sucking, especialy further in the dungeon. What you want is damage, but there wasn't many options for me on that part, but pick the trait where Heaven's Strike leaves behind damaging pools - that kinda has devastating result. I also managed to find the same melee companion twice, so I had 4 of that companion, and they shredded like anything in their path!

Currently trying Linda, but she is a nightmare. She has no "luck", so she won't have gold or gems, so don't even think about opening gem-chests, gamble, or other nonsense. Buy a tiny amount of grace and relic, and upp the best you scrap.
Actualy, she walks through normal levels like piece of cake, though don't even thinik about any of the rashing guardian, or combo subquests.
The real problem are the bosses, because this character don't have DPS, the secondary attacks do practicaly nothing, the bosses are like immun to stun (and likely slow too).
Oh, and she doesn't have HP either.
What you can do? Well, I feel we have to try guardian rage. So extend its period as much as you can. And give yourself primary attack damage. And penetration, otherwise you'll be F-ed hard in many situations. Posion would be cool on top of it, but most of the times you'll have to accept knockback, if luck the plus stun by chance variant. But otherwise she sucks.
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Managed to do it buffing critical chance, critical damage, poison, burn, even found some dodge, AND that bloody boss had damaging pools instead of lasers.
Oh, and also had the relic which instantly refills your rage, so I could do instant double rage on the bugger.

Man, Joey sucks! He's slow, we all know. The problem is, he only gets as far as I got, gimmicky buffs, and no DMG-buff, what'd be the sole core of the character, no matter what!
The core to play with Joey is to get either regeneration or a recastable shield, preferably both. Then do your best, and hope for easy bosses which you can smash. I somehow got the robot both times.

Mark is an absolutely ridiculous character.
According to my experience he gains a ton of gems, and not just a small amount of gold, but there's no use for them! Barely any grace/permanent charm to buy, not even if you spend gems to roll the shop (btw, you can only re-roll the shops once per occasion!). No "Gemstone Hungry" ever met. Like no extra damage talent. He'd also need AoE damage against dlvl 13 bosses, but of course that's not possible either.
What you can aim for though is whip leaves a spot of damage, also cyclone for extra kick. One extra range is also ok. As th character is good at evading, and I rleiably gained extra speed through talent, if you find DMG for speed you might pick that up. Otherwise do your best. Oh, and with lacking like everything, try out the laser traps, they seem to cover a good portion of the field.

knife boy is absolutely horrible in Family Trial, no wonder he is at the end of the "win with each family member" chain. Has no regeneration, only something when maxmim frenzy is in effect. I've seen no extension of franzy duration. Guardian Rage as you remember for this character does nothing but puts you at maximum frenzy. And in this mode no, you can't extend the period your frenzy-boost lasts at all! And the character is a single-target melee unit. Oh, and the "doing an exectute attack (single target attack while in shadow mode) puts you at maximum frenzy" DOES NOT WORK - maybe if you actualy kills an enemy with it, but how does that help you? That's how.
UPDATE: Finaly the game gave all what the character needed: more critical chance, critical damage, dodge, healing chance when attack (plus John's special on critical). Then you just have to cross fingers. And use ALL the abilities, and I mean all of them. The hide in shadows skill buys you time, and during a regular level lets you run to safety. Oh, the relics were also important: refilling potion and the shield which says negates the first 2 hits, but I suspect at least in this mode it is more of a duration-thing. This later doesn't seem ideal, but I though I give it a try, and through extensive use it turned useful. I also managed to get two consumable charms on me, a shield and a healing item at the last shop. AND I also had the extra dmg per gemstone thingy too. So pretty close to an ideal run here. I'll never touch this character again (ok, I still need to play it a couple of levels for unlock its buff - which I'll never use of course), but you get what I say.
NOTE: in this mode the "stay at maximujm frenzy until enemy hits you" does not work this way, but gives a nice extended period to do frenzy.
Also it seems the laser-beams during a bossfight can be avoided/crossed w/o damage if you use evade to cross them.

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On the Gemstone Hungry grace: I went from 17 to 14 to 9 when trying this. The additional damage's change was: +82,1 -> +108,3 -> +111,9.
So spending on it is good, but not wirth the three star grade.

The "Taskmaster" buff at the start gives you a free "levelup". I'd likely go for a sure pure DMG, or maybe a fix walk/run speed boost though.