Does this game, like Yakuza 3, have any "must-have" skills/substories to complete?

[Saza]

Yakuza 3 was kind of a pain to get through if I didn't immediately do Revelations and Komaki the moment they were available. Is there any of the sort of skills/substories/challenges that I should do in 4, or is it a lot more forgiving of a game?

[Zatsu]

i've only played 15 hs and i'm on the 3rd character, but for now i didn't have any trouble with any of the fights, as long as you have healing items you can do them just fine since they don't block as much as yakuza 3. The only frustrating fight i have come across is the 3rd character's master which is especially anoying because you can't use healing items.

[Astrophizz]

I'm only near the end of the 2nd character's arc but the IF7-R fights handy to expand the usefulness of heat. I found the 1st character's master's rewards way more useful than the 2nd one, though the unarmed attack power and heat action power upgrades for the 2nd one are nice.

[guts' theme (Cut & Looped)]

combo extenders

[Our Holiest Host, Father Faust]

Combo Extenders for all 4, for Saejima you'll want his attack speed boost and his super armor skill, the damage boosters from beating IF7-R

[Perquisitore]

For Saejima go for attack speed, otherwise whatever you want.