Story mode is WIP, adventure mode has more content.
Also, the combat system is the same in both modes.
The combat ain't that hard, it can seem like it's daunting at a first glance, but it's not that complicated, just need to watch your stamina, footing and stance, what action leads to what stance and what to use against different enemies.
Or just level up spring attack, crushing blow, fade away and second wind, spam spring attack and crushing blow (they follow one another in stances) and once you're running out of stamina or footing, use fade away and then second win to regain stamina and composure, then just return to spamming SA/CB, rinse and repeat, easiest build and pretty much relies on your gear and attributes to be a succesful tactic.