I have been playing Octopath Traveler lately, owing to a certain sale and recommendations from two friends. The combat in this game flows very nicely, and I want to understand why.
Here's a rough overview of how combat works. In Octopath Traveler encounters you control a party of up to four characters battling up to (?) five or maybe six enemies. Combat is structured in turns: Each turn every party member and enemy acts once in an order determined by their speeds. A party member on their turn can attack a single enemy, can use a skill unique to that character which may attack enemies, buff themselves or others, or debuff enemies, or they can use anitem or other special ability. Each enemy has one to five damage type weaknesses (for example, sword, axe, fire, and ice) and a "guard" number (say 3). If you hit an enemy with a damage type they are vulnerable to, that enemy takes extra damage vs. if they weren't weak to that damage type, and they lose one guard point per hit. So if you hit an enemy with its weakness twice, they lose two gaurd points. If an enemy runs out of guard points, they break, meaning they cannot act this turn and they lose their action next turn. Broken targets also take double damage until they recover and they recover the same turn they get to act again. When an enemy recovers, their guard number resets to its initial value.
On top of that, combat has a battle points (BP) system. They can spend up to 3 BP in a single turn to make their attack or skill use more effective: Buffs last longer, attacks hit more times, and attack skills simply deal more damage. Every turn, your party members gain a single BP, capping out at 5. However, a character won't gain BP if they spent BP last turn. This gives you an incentive to save your BP until you can use 3 at once.
An interesting feature of the "guard break" system is that it makes your choices more complicated/interesting. You do not necessarily want to focus on dealing lots of damage to one enemy. You may rather break as many enemies as possible to avoid damage, status effects, et cetera, rather than going for the kill on one enemy at a time. It also makes area-of-effect (AOE) skills better, because they can remove one guard point from every enemy whose weakness they match. Normally, only BP-charged attacks can remove more than one guard point per act – when charged with BP skills don't hit more, unlike attacks, rather they deal more damage with their one hit.
I find that spreading attacks around especially makes sense for hallway fights (that is: random encounters). In hallway fights enemies may not deal enough damage to be a real threat but do deal enough to wear your resources down over many such fights (and there are many). Breaking multiple enemies means you avoid more damage since those enemies don't get to act while broken. It's especially good in this scenario because often each individual enemy is weak enough you can quickly kill them by the time you've broken them.
This seems to work well with the battle points/BP system. Because BP don't accrue the turn after you use a BP, you want to save up and use as many as possible in one go. If you use a BP the same turn you break an enemy, you're foregoing an extra bit of damage next turn, when the same enemy can't move. You get X damage, whereas if you waited you could get X + 1 damage. Of course you may risk not actually killing them before they recover from the break. Beyond this, breaking an enemy gives you an opportunity (1) to attack, and (2) to spend your BP attacking and deal lots of damage.
The "break" system also seems to make glass cannon characters better. Once the strongest enemy is broken, they get a chance to do lots of damage atlittle risk because of the broken enemy losing their turn and the damage multiplier that applies while they are broken.
It's an interesting system. "Breaking" is more important to it than I might have guessed. It's interesting the way that "breaking" and battle points complement each other, too.