Now that we have a fair number of people playing, why not start putting together a bit more robust FAQ/guide for the game, especially in case other people are curious to try it out?
Starting the game*
When you begin the game, it lets you select from any of the starter cards, but after a brief tutorial battle, it lets you choose again; this second choice is the one you stick with, so make it wisely. Note that you get strong cards for progressing through the normal dungeons (generally at the end of each 'region'), and if they are always the same, then you get a fire, water, and light card (in that order). This means that arguably the wind and darkness starters are most useful early on, at least for the sake of elemental variety (which is important as the dungeons start getting more difficult).
However, feel free to choose which card you like the best if you feel you have to have a particular one, but also keep in mind: all of the starter cards are available through the basic gacha.
*I wrote this section from memory way after the fact. If I'm wrong or missing something, please by all means correct me so I can fix the guide.
Playing the game
DarkAlice did a wonderful job of pointing out what the specific buttons do on various screens, but I want to take this into even further detail.
Home Screen
Also, called "My Page", this is the main screen from which you will do everything else.
A: 'My Page' button. Since this IS 'My Page', it won't do anything here, but on any other screen, this button will return you to this homepage.
B: Player level and EXP bar. Player level influences several things, including: your maximum stamina, maximum cost total, number of cards you can have in your collection at a time, and max number of friends.
C: Stamina in numerical and visual representation. Going into dungeons requires stamina, and it regenerates at a rate of 1 per 3 minutes.
Stamina increases with level (allowing you to store more of it) and it is also fully and instantly restored when you level up.
D: Time (in 24hour format) at which stamina will be fully restored through natural regeneration
E: Dungeon. Click this to go to a dungeon and do battle, earning cards and items, as well as money and player EXP.
F: Deck management. Arrange your deck and power up your cards here.
G: Album. View cards you have obtained before, and their special scenes.
H: Gacha. Earn new cards...if you're lucky.
I: Quest. Turn in items, or agree to slay monsters for money or better items.
J: Friend. View your friend list and add new friends.
K: Shop. Takes DMM points, i.e. real money. Your call, but not recommended.
L: Item. View items you currently hold.
M: Option. Adjust volume of BGM or SFX...and that's it.
N: Title. You get titles for accomplishing certain tasks (slay 1000 monsters, enter 1000 dungeons, etc). Equip them here.
O: Leader. This shows (the basic form of) the card in the leader position of your deck. Sometimes they have a few words to say, but in Japanese.
Dungeon Type Page
A: Normal Dungeons. Also known as 'story dungeons', not that there is much of a story.
B: Event Dungeons. Usually just challenge dungeons (not sure what those are for), but other holiday/event dungeons will appear here during a special event, letting you get special cards.
C: Daily Dungeons*.
*I personally don't really know the function of daily dungeons, at least as far as how they differ from the 'normal' ones. If anyone wants to help me out here, that would be great.
Dungeon Selection Page
A: Region List. Starting region is at the bottom, with more difficult ones as you go up.
B: Dungeon list. Ordered the same way as the region list.
Note that completing a dungeon opens up the next one, and completing all dungeons in a region opens the next region.
C: Available items. Items are in order of rarity within that dungeon; 1st item is common, 2nd is uncommon, and 3rd is rare. If you see a purple block in place of an item, it means you haven't gotten that item form the dungeon yet.
D: Available cards. When you run a dungeon, you will get (at least early on) six cards from it, chosen from the options you see here. The top card is the more common one, while the bottom card is much harder to obtain from that dungeon. Note that cards which are rare in one dungeon may be common in another (and vice versa in some cases).
Deck and Friend Selection Page
A: Deck Selection. You can have up to 5 decks set up at a time, and these buttons can be used to select one.
B: Friend Selection window. When you enter a dungeon, you take the 4 cards in your deck, and one extra card from someone else. When you have people on your friend list, they show up with "Friend" in green; choosing them gives you a bonus to FP when you finish the dungeon. Otherwise, you can borrow the Leader card of people you don't know (all marked "Guest" in purple).
C: Elemental Sort. First button lists all elements. The rest are, in order: fire, water, wind, light, dark, and null.
D: Statistic sort. A drop down window withthe following sort options, top to bottom: Max HP, Attack Power, Skill Points, High BL, Low BL, High Card LV, Low Card LV, High Rarity, Low Rarity. Of these, it's worth noting that at times Low BL can be very helpful, see BL in dungeons below.
Dungeon Confirmation Page
This page allows you to confirm your selectiosn before entering a dungeon.
A: This blue button begins the dungeon. There's nothing much else to do here, unless you've made a mistake and need to back out.
Inside a Dungeon
This is the main dungeon screen. Not a lot of options here, but let's break down the details of what you are seeing.
A: Step button. Hitting this takes one 'step' in the dungeon. If you click and hold on the button, it will start auto walking, which will continue through the dungeon automatically, only pausing for input during combat.
B: Dungeon progress, in steps. Each dungeon takes a certain number of 'steps' to clear (in this case 30). The last step will always be a boss encounter.
C: Obtained EXP. This is how much EXP you have obtained in the dungeon so far. Whne you complete the dungeon, this amount is added to your player EXP count (cards do not get this).
D: Obtained Gems. This is the game's currency for levelling and fusing cards.
E: You current Party
F: BL. This is like a card's individual stamina. Note that the leader card does not have a umerical value for this.*
G: HP. This is the card's health. If it hits 0, the card is KO'd and cannot be used for the rest of the dungeon. The Leader card is an exception; if the leader is KO'd, but you manage to win the battle, the Leader is revived at the end of the battle with 1 HP.
H: Skill points. Consumed when a card uses skills. Think MP.
I: Magic Stones. Clicking this button opens the magic stone menu, which gives you access to a variety of beneficial effects...but the stones are generally better saved for the gacha. Your choice in the end. (details on magic stone menu to come)
More on BL: A card can only act in battle if its BL is full. Once it participates in battle (regardless of whether it actually got to attack or not), BL is set to 0, and recovers by 1 with every step. The Leader card's BL is considred to always be full. Similarly, a card with a max BL of 1 will be restored on the first step after battle, so they have no problem participating in consecutive battles. For Max BL values of 2 or greater, if a card acts in a battle, and you get into another battle on the very next step, they will be unable to participate as they will be in a 'recovery' phase. The guest card in this image has a max of 5 BL, which means that after being in a battle, they cannot participate in another battle for 4 steps. One of the real challenges of this game is managing your cards so you don't end up in a battle with all cards besides your leader in recovery. Early on, there are some decently strong cards with low BL that let you use them frequently, but this gets difficult to keep up.
During a battle
When in battle, a new menu shows up.
A: Participation check box. Checking this box will make the card participate in the battle; the Leader must always participate.
B: Participate Button. Has the same effect as checking the box mentioned in A.
C: Regular attack. See D below.
D: Skill. This will tell the character to use their offensive skill instead of a normal attack. This will depelte their Skill points (blue bar), and not all characters have skills like this; note the grayed out skill button in the middle.
E: Begin Turn. This will begin the battle with the settings you have selected using everything marked until now.
F: Force attack. This will take all cards currently able to act and force them to use a normal attack. This overrides any selections made above.
G: Force skill. This button forces any characters that can to use their offensive skill. Characters without a skill (or without SP to use it) use a normal attack. Again, this overrides other selections made above.
H: Resets commands. This sets it so that only your leader will sue a default attack. In case you need to rethink your actions before taking the turn, or if you only want the leader to participate, this is a nifty shortcut.
During a battle, Part 2.
Once you've made your selections for attacks, battle begins.
A: Auto-Battle Notice. Once you make your selections for the first turn, following turns will have the participating characters automatically use normal attacks. If you want them to use skills after the first turn, you must click to stop auto-battle, and then make selections again.
B: Enemy display. This is a picture of the enemy, with a health bar below. Note that enemies are color-coded by their element.
Elemental affinities are the other challenging aspect of this game. Even stronger cards can have a hard time against certain elements.
There are six elements in the game: Fire, Water, Wind, Light, Dark, and Null.
Fire is strong against Wind, Wind is strong against water, and Water is strong against Fire (think Pokemon or the like). I'm not entirely sure how the other three elements fit in though.
C: Enemy health bar. Separate for each enemy, of course. Also color coded by element.
Deck Management
A: Deck Setup
B: Card Levelling
C: Card Fusion
D: Card Collection
E: Card Locking
F: Sell Cards
Remember that you can click the "My Page" button to quickly go back to the main screen from this or any of the following pages.
Deck Setup
The first page under Deck Management is where we set up our deck, so let's take another look at it.
A: Player skills. Click the blue-grey bar to configure these.
B: Party member skills. These are the skills the cards in your current deck have, and are tied to each card.
C: Deck. These are the four cards (plus the one guest card you choose before a dungeon for a party of five) that you enter a dungeon with. Note that the left-most card is made your current deck's Leader. Your leader has unlimited BL in a dungeon, so use that to your advantage, but remember that it's also the card other players get when they use you as a guest.
D: Deck Name. You can change this as you like, then click the button next to it to set that as the current deck's name.
E: Deck Selection. You can have up to five decks at a time. Use these buttons to select one to configure. Each deck's name is separate.
F: Cost. Each card has a Cost Value, and as a player, you have a maximum cost limit. The cost value of the cards in your deck cannot exceed this limit. For example, here I currently have a max of 87, and since the total cost of the cards in this deck only add up to 61, I have nothing to worry about. However, if I wanted to use four cards that each had a cost of 25, I wouldn't be able to, because it far exceeds the maximum cost I can use as a player. I believe a player's maximum Cost value increases with their level?
G: Collection Window. This window shows all cards you have on hand, which you can use to alter your deck. You can swap cards simply by dragging and dropping.
H: Sort options. These work just as they did in friend card selection from the dungeons.
I: Collection current count/max. When you start the game, you can only have up to 50 cards on hand at a time. This value gradually increases as you level up, however.
You can select any card by clicking it, which will bring up the Card Status Page
Card Status Page
This page displays various statistics for a selected Card
A: Name
B: Current Level
C: Element
D: EXP Bar
E: Cost. Cost influences what kind of deck you can build. A card's cost is related to its overall effectiveness (weak cards cost less, but strong ones cost a lot more). Your deck's combined cost cannot exceed your player maximum.
F: BL
G: HP
H: Attack Power
I: Skill Points
J: Active Skill. This is the skill that is available to use in battle, though not all cards have one (this card does not).
K: Passive, or 'Auto' Skills. These skills are always in effect, and usually involve the reduction of certain damage types.
L: Illustrator's Name, in Japanese.
M: Rarity. Note that the color of the heart behind the rarity also shows you the element(red=fire, blue=water, green=wind, yellow=light, purple=dark, gray=null)
Rarity is sorted into 6 categories: N, HN, R, HR, SR, and UR. The higher the rarity, the better the card, but the harder it is to get.
N: Form Level. Each heart represents a possible form level, and the number of 'filled-in' hearts represents the current level. For example, this card is on its first form, but has another possible form that it can change into via Fusion (1 heart is filled in of two hearts total). Some cards have 3 or 4 possible forms, while some only have 1 (no fusion possible in that case). When a card gets its next form, it goes up in rarity. See Fusion below.
Card Levelling
On this page, you can sacrifice a number of cards in order to strengthen another one.
A: Base Card slot. This is where you put the card you want to level. Note that each card has a max level, and once you reach it, you will no longer be able to level it (though you may be able to fuse it).
B: Cards to be consumed. You can drag and drop up to ten cards into this area for the purpose of sacrificing them to level the base card. The cards you give up this way are gone forever, so it's best to use the common drops you get from running dungeons.
IMPORTANT: Note that using multiple cards at a time gives you bonus exp. 1 card gives you 1000 exp, 2 cards give you 2370 exp, 3 cards give you 4111 EXP, and so on. Therefore, it's generally better to always use more cards at a time, unless you're nearing the base card's maximum level. Note that using cards of different elemental types seems to also give a bit more EXP.
(Example: using ten common cards at once gives somewhere in the range of 35000 EXP; that's the same as 35 cards done individually)
E: Current/Max fodder card count. You can only sacrifice up to ten cards at a time when leveling. As mentioned above, it's almost always better to use more.
F: Current gems, cost of levelling, and Gem count after levelling.
G: Confirmation. Click this button to actually level the card.
Card Fusion
This is how you upgrade a card's form.
A: Base Card Slot. This is where you put the card you want to evolve to its next form. Note that this card must be at its max level.
B: Partner Card Slot. This is where you put the supplementary card for fusion. Note that this card must be the same as the base card, but it does not have to be at its max level. However, if it is at the max level, the Base cards evolved form will get a slight bonus to its stats (something like a 5% increase I believe).
The window on the left with your Gems values and the confirmation button are the same as they were in levelling.
Note that card fusion takes TWO of the same card and gives you back ONE upgraded form of the card; the partner is sacrificed to upgrade the base.
Card Collection
This window lets you more easily see all of the cards you currently have on hand. There's not really anything new to this window that hasn't been covered in other parts of the FAQ already.
Card Locking
This window is similar to the collection window, but has a few key differences. Primarily, there is a lock button on each card's icon, which allows you to quickly decide which cards you want locked or unlocked.
Locking a card prevents you from taking any action that would dispose of it. This means that a locked card cannot be Sold, Fused*, or sacrificed to level another card. Note that locked cards can still be included in your active decks, and can be set as the base card for levelling; these actions have no detrimental effect on the card.
*Note here that Locking a card prevents it from being used as the Base AND/OR Partner card in a fusion. This is because the card you get back is a different form, and technically speaking has a different Card ID. Only unlocked cards can be fused.
A: Lock button. This is what you use to Lock/Unlock a card. A gold lock shows that the card is currently Locked.
B: Current/Max Locked Card count. You can only lock a certain number of cards at a time. In my case, that max is 35. Even though I can hold 50 cards at a time, I can only lock up to 35 of them at once.
Card Selling
On this page you can select cards to sell for gems*.
A: Check box. Use these to select which cards you want to sell. You can sell up to 10 at a time.
B: Card selection count (can only sell 10 at a time), current gems, value of selected cards, and gem count after sale.
C: Confirm button.
*Note that selling cards is not all that helpful or necessary. at least in the case of common dungeon drops. These are generally better being used to level the cards you want to make use of in your deck.
Album Page
A: Sort options. Unless you know what you're doing, don't touch this, as the default sort (by ID number) is easy to work with.
B: Page selection. Click a number to jump to that page, or click the arrows to move between pages.
C: Card Display. Cards you've obtained are arranged here. Click one to view its details.
D: Monster Album. Not of much use to those who cannot read Japanese, unfortunately.
Album Details Page
A lot of these details are the same as the card details page before. There is some other useful information here, though.
A: ID #
B: Max Level
C: Rescue Scene. Almost always a light bondage image.
D: ?
E: Dungeon Event Scene. For Cards you get for clearing certain dungeons (such as this one), you get an H-scene with it, which you can view again here.
Other details are the same as they were in the Card Details page earlier
Gacha Page
The Gacha page is where you gamble for new cards.
A: Normal Gacha. This gacha uses Friend Points (FP). You will mainly get Normal (N) cards from this Gacha, but it has a decent chance for rares. All of the starters are available through the Normal Gacha.
B: Silver Gacha. This Gacha uses magic stones as currency, but has a much higher chance for better cards.
C: Gold Gacha. This is an upgraded version of the Silver Gacha. For even more Magic Stones, you have an even better chance of rarer cards.
D: Current FP. You can get FP by logging in daily (I believe you get more by logging on consecutive days) or by having a friend's Leader card join you in a dungeon (30 FP per trip). If you don't have many friends in the game, you can take random guests (but you only get 10 FP per trip this way). At The end of a dungeon runm you have the option to send them items or cards received for a bonus to FP.
E: Current Magic Stone Count. Magic Stones can be acquired by logging in daily and through some quests.
Note that each Gacha has two options. The left option is a one-shot gacha, while the right one is a multipack economy gacha. For example, on the basic gacha, you can get one random card for 100 FP, or 11 random cards for 1000 FP (that's one free card each time, and thus I highly recommend always choosing the right option for a gacha for better value).