This is a guide of some hopefully useful information, from my experience playing through the game. I only intend to talk about gameplay here - the story is great and fun, and you can easily experience that yourself. I beat the game in about 13 hours, playing on Normal difficulty, which I found taxing but ultimately achievable. (For reference, I am not a skilled gamer; I came for the VN elements, and was too stubborn to turn down the difficulty sliders - more on that in General Gameplay.) What I'm putting here are things that I had questions on, or would have enjoyed knowing going in.

The game is generally divided between two sections - road-trip conversations and combat. The characters have a series of conversations as they drive towards their destiny (with occasional roadside stops). While doing so, and making your conversational choices, you will also guide your car between three lanes of the road to select (or avoid) which fights and stops you want to have.

The fighting gameplay is what I'm going to focus on here. (If you're looking for story spoilers, I'm going to do my best to avoid them - just enjoy your time with these adorable people.) Combat is real-time, between your party on one side and the enemies on the other. Each character has a button, which activates their current ability and puts it in a cool-down state for a few seconds; during this time other characters can act (as will enemies), and once the cooldown has passed, the ability can be activated again. By equipping various trinkets to your characters, you can change up their abilities - each character can equip three different trinkets, which correspond to three different 'pages' in combat. Rotating to the next 'page' of abilities (with W) gives you the next set of abilities for each character, on a different set of cooldowns, so it's often faster to switch and use the new abilities than waiting for the cooldowns to finish. After the third 'page', Grace will use her sword for a powerful attack, and you will be returned to the first 'page.' (These abilities will be on their initial cooldown again; you can't just flip through without pause. :)

Difficulty Settings
I played through on Normal, using a keyboard. I think this was a mistake. :)

At the very least, the game feels designed for a controller - the layout of default buttons left my hand a bit cramped, and I never felt confident navigating the equipment menu because I couldn't always keep straight which button did the thing with the trinket that I wanted... and you interact with trinkets a lot. I would highly recommend use of a gamepad of some sort instead, if that's an option for you.

There are two default difficulty options. As far as I know, there's no loss of rewards for easier settings, so don't feel shy about using them.

The first is Story Mode. This will do a number of things to make the fights easier, such as restoring your health after each battle, and slowing the battle down. On Normal, health lost is gone until you reach a shrine where you can rest and heal, or you use an item _outside_ of battle to restore it. In the battle itself, Sam (or item use) can heal characters - but this grey health bar disappears at the end of combat. Any damage below that is permanent and will carry into the next fight, which makes the series of battles that you fight more and more taxing as they go on, because you will want to spend time at the beginning of each fight just getting up to strength. (Characters who end the battle Defeated will begin at 1% for the next fight.)

The second option is Battle Speed. (Story Mode will turn this down automatically.) With the speed halved, it's easier to chain together combos for extra attack strength. Additionally, this will pause the game while you select targets for healing - normally characters will use their abilities on the targeted enemy, but when Sam uses healing abilities, you need to hit additional buttons to select which friendly character you want to target. (By default it will select Valentin, your party tank; use the directional keys to select a different person, and hit Z again to heal them instead. This will change the default for that battle to the new person, so you can double-tap Z to continue healing.) At full speed, I found these extra presses would throw off my rhythm, especially while trying to keep an eye on everything else happening in the battle.

There is a third option called the Devil Clock that you will unlock during the course of play - this allows you to add extra difficulty to fights in exchange for a special currency. These added challenges will activate in fights on their own short timers - if you can defeat enemies quickly, you can avoid the problem, or at least get in a few good hits first. Some challenges include raising the level of enemies, adding additional damage to their attacks, blocking the first hit of chained attacks, or other changes to how you have to deal with threats. If you pause the game in combat, the challenges will be explained in more detail. The currency is (mostly) used for purchasing stickers - these let you upgrade trinkets without using up an item that might otherwise still be valuable. For the most part, I found that the Devil Clock was a good bargain - if I was handling the fight to begin with, the extra challenge was minor, and I appreciated being able to upgrade trinkets without throwing lots of Gas Points into it. Also, there are Achievements for beating various Bosses with the Devil Clock active, if that's a thing you're going for.

Each character equips three trinkets to set their abilities in battle - the same trinket will give different abilities to different characters, depending on their affinities; the trinket will have several abilities listed in colored bars, and each character has two colors on their equipment slots that will show you which abilities they will gain. (The trinket will also display their portrait when you examine the abilities in detail.) This gives each character their specializations; eg, Sam is the only one to get healing abilities, Valentin is the only one to get tanking abilities, etc.

Trinkets are your main form of upgrades and leveling during the game. Each trinket has a rank (from 1 to 9) and can be upgraded to a + version (1+ to 9+), which functions as the next rank higher. Rank matters because it determines how effective the ability will be - a higher ranked ability will deal double damage to a lower ranked monster; conversely, only half as much damage to a monster of higher rank. Your character's rank based on the lowest ranked trinket you have equipped, and will determine how much damage you take in turn from monster attacks - a rank 4 character will take much more damage from a rank 5 monster, and much less from a rank 3 one.

You upgrade a trinket by 'feeding' it a number of other items - four items to turn a rank 1 into 1+, up to thirty-six to upgrade a rank 9 trinket. These items can be anything - other trinkets, healing items, or most usefully, stickers - which have no other use and are obtained from the Devil Clock. Once a character is equipped with three upgraded items (eg, 1+) they will be ranked higher (eg, rank 2); once all of your characters are at a given rank, it will unlock purchasing items of that rank from the shop, so that you can upgrade them in turn. (Also, upgrading trinkets will unlock a portion of the story associated with them; each trinket has three story parts, one unlocked for having the item, one for having upgraded it, and one for using it in combat.)

Now, it is important to know that enemies will also scale along with your party - the encounters along the road will be approximately -1 to +1 of your party's ranks. So why rank up, if you're always going to stay mostly even? Because new higher ranks of trinkets offer new and useful abilities for your party. I'm not going to go into detail on what all the abilities on offer are, in part because discovering the new toys on offer is part of the fun.
**Edited to add** Per the comments below, I'm not certain if the enemies actually scale, or if the shops just won't sell you gear at a rank too much above the enemies that appear on that stretch of the road. Further research needed. **Edit**


A few things that are useful to know, however:
Elements - Around rank 3 or 4 (and reoccurring later), you'll start to find trinkets that apply elements to your attack. These allow you to take advantage of the elemental weaknesses of enemies, at the cost of healing enemies who share that element. (Water beats Fire, Fire beats Leaf, Leaf beats Water) There are even trinkets which will apply their element to every attack the equipped character makes, allowing you to have multiple elements at once. This is, in my opinion, a trap.

At this rank, you will also start getting Field Guides (from purchasing the Support Bundle for healing items, etc) which allow you to see details about an enemy by using them from the pause screen - it will tell you any elemental affinity, as well as the target's hit points, stagger point, and other useful information. The affinity is also indicated by an icon next to the target's name while in active combat. However, I found that in the pace of battle I didn't have time to check that, or to rotate through targets to take advantage of weaknesses, and often found myself several rounds in wondering why I didn't seem to be killing them... only to find that I had a matching element on one or more characters and was doing more healing than damage while we fought. Easier difficulty settings might mitigate this by slowing things down, but you will still have to pay closer attention to which character/ability is striking which enemy, and because you can see the number of enemies you will fight, but not which types, there isn't a way to change equipment to ensure a favorable match-up ahead of time.

There are still some element-free attacks available to you at these ranks, but you'll likely want some of the abilities that are tied to elements, especially as you buy your first sets. Be sure to pay attention to which characters you put them on, and where in the rotation they'll come up so that you can manage your combats.

**Edited to add** Per the dev's Twitter, if an attack has multiple elements, the game will use the best one for the attack, so that should at least mitigate the healing them by accident. **Edit**

There are two other elements you'll encounter later that aren't as fraught.
Atomic is an element that is strong against any elemental target, and heals none of them. There is also a combat item that will give all of a character's attacks the atomic element for a single battle.
Rust is not a traditional element, but applies a damage-over-time and a building meter that can be detonated for even more damage by the next ability with Rust.

Another thing that appears on trinkets in later ranks is Half- abilities. These do half as much damage (or healing) to the target, but also have half the normal cooldown - great for maintaining and increasing chain attacks.

The last piece of equipment to mention is Grace's sword. She will attack with it after you switch from the third 'page' of abilities, dealing lots of stagger damage to the targeted enemy. It has a special rank, which is that it doesn't need to be upgraded, but functions at the rank of the other trinkets equipped to her. The DLC offers her another sword option, which is also pretty cool. This one automatically kills a single enemy or boss-phase, once per combat. After it's been used, you just rotate back to the first 'page' of character abilities so in long fights it's not as useful, but I found it incredibly nice for most of the road combat to just be able to delete the most annoying enemy at the start of the fight.

The various bosses you fight at the end of each Act are fun, and do add a lot to the story so I don't want to talk in detail about them. I'm including this here just to talk about the few bits that are specifically combat related. I'm going to try to put a small hint first and then a more spoiler-ish comment after.

Act I Boss: When you can't hit it any more, maybe try a different tactic? This boss wants to make sure you know how to switch targets. When it starts to fade into invincibility, punch the angel instead. She's tough, she can take it, and her blood will let you target the boss again.

Act II Boss: Make sure you watch your elements. This one I'm not as sure one? I had gone through the DLC before fighting this one, and so I'd ranked up my trinkets back to a point where my attacks were all unaligned again. I think I remember it switching between elements, but mostly I just punched until it stopped fighting.

Act III Boss: Sam should be healing. This enemy avoids attacking Sam for story reasons, while dealing out lots of damage to everyone else. Make sure she's able to keep getting everyone back on their feet and you'll get through it.

Act IV Boss: This is the end; remember what you're fighting for. There are a lot of phases in this boss fight, which will test your endurance and mastery of the other systems. The last phase splits Grace off from the rest of the party; you can still heal her, but what you really need to do it use the Sword of Fate several times to defeat the Machine Devil.

DLC: [spoilers]Lots of little fights on the beach, but that last one's a doozy.[/spoiler] I got beaten several times here. I'm still not sure who the 'best' target for the Zantetsuken is. Sometimes I just couldn't heal fast enough and my items ran out and I died. Once I took out the partner and could heal my party up, but couldn't deal enough damage to overcome the enemy's own heals - I think I spent thirty minutes trading blows and getting nowhere, with their health going between 1/4 and 3/4 the whole time, before discovering I couldn't run. I quit and reloaded from the previous save (because I'd also used up my whole item stock during that fight) and went to grind out new trinkets on the beach. Still don't know if there was a more elegant way of doing that fight.

No Going Back
One last important bit - after the final boss fight, and credits, there's a staging area that will allow you to access new DLC that you haven't yet completed, and look at your various trinkets, etc. You do not get to go back on the road again, so if there's achievements you're still trying to do, quests to turn in, conversations to have, be sure to try and avoid the final boss fight until you're set to go. Ask me how I know...
I have two quests completed but not turned in; I think I missed a stop somewhere? Or maybe I just needed to keep driving until I found one? And according to the Feats list, there's several road conversations I missed too - I don't know if I have to replay and choose different options of what to say to get those, or how that works.


Anyway, hope this has been helpful to someone. If I've got anything wrong, please tell me. If you've got any other questions too, feel free to ask and I'll see what I can do. :)

Have fun and enjoy the story!