To easily beat the game, you only need Agility and Stamina.

AGI:

STM:

You'll dodge plenty of attacks and survive any that actually land.
You can mix STR (Strength) for +health and INT (Intelligence) for +elemental resistance.

With this in mind, you can make your CHR (Critical Hit Rate) up to 100% and... well, for whatever reason my CHD (Critical Hit Damage) won't go above 279% but I'm yet to craft something above 280% so I'll just say that 280% is the CAP, even though there's a 350% CHD item and they don't seem to stack. Anyway, as you invest AGI you can remove items with CHR and replace them with more attributes to make the character deal more damage or survive better (pft).

Just to simplify all this, 1,000 HP is plenty for any instance/boss as long as you have approximately 280~300++ AGI for constant dodge and accuracy.

I also want to mention a particular item I have equipped on almost every character...

== Smithy ==

I'm not sure if this effect can be stacked (i.e. having 2 or 3 party members wearing them so instead of 10% it'd be 20% or 30%) but this will also make your AGI beneficial.

== OUTRO ==

Achievements work 100% and once you accomplish this, the game has no more objectives besides upgrading characters and upgrading infinite adventure (meh).

To craft the best items you need 284 attribute points for that specific shop. (max is 100%).

To make gold, craft whatever and sell it and invest in character progression.

Spells are not necessary. You will not be using them at all - probably only for the mission and achievement but you'll need to research them all for the sake of the achievement.

Okiki (Hot Springs) boss is the hardest boss/monster, nothing else will stop you. Not even the infinite adventure.

You only need your characters at lvl.30 to beat the game.

This game isn't worth 10dorra, even 8dorra would be questionable as it feels unfinished/ rushed.