Found this on ULMF and I don't know if there is one here already or not, I can't find it if there is , so here it goes!

What is Hellfire Girls?

It is a card based, harem building game that allows you to use erotic cards to engage in battles with other players. You will collect girls/cards and play through bawdy scenarios to level up, and train your girls to gain attack strength.




How do I level up?

You can level yourself up overall by completing missions.
You can level your individual cards up by training the girls, or completing a lesson.




How do I train the girls?

You train girls in the "Training" section. If you have two of the same card, that card is considered trainable. Select the girl you wish to train, you will then be prompted to select her duplicate. By pressing "Start Training", the cards will be combined into one higher level card.






How do I complete missions?

You complete missions by selecting “Mission” from the home page and then selecting the “Do It” option on the page. This will also reward you with new cards and puzzle pieces that can be used in other parts of the game.






How do I complete a lesson?

You complete lessons by selecting a base card from your deck that you would like to strengthen, and adding other cards to the “Training Card” section. By pressing “Lesson Start” the cards will then be combined, this will level up the base card. All other cards that were selected will disappear from your deck.




How do I complete assignments?

On the home page under the “Assignment” section you will be able to form a group of girls and send them on the assignment, they will return, when the time of the tutorial has reached 0, with any combinations of Eros, gacha points, gifts etc.




What are Eros, how do I get them?

Eros are the currency of Hellfire Girls. You can gain them by completing missions, winning battles or by completing assignments.




How do I get more cards/girls?

You can get more girls by visiting the “Gacha” section on the home page and cashing in to receive more girls, by winning a battle or throughout the “Mission” component where you will be periodically rewarded with girls during and after the mission.






Help! I can’t win a battle.

If you are having issues winning a battle, try staying away from the missions for a while ( these will cause you to level up and be placed in a more difficult bracket when battling) and focus on leveling up your girls individually. Make sure your “Leader” girl is very strong as well as your attack and defense decks. Also try and create a viable “Group 2” deck, as they will act as backup when the “Group 1” deck has been defeated.








How do I complete a puzzle? Is it useful?

You can complete puzzles by selecting “Piece” from the drop down menu, choosing the puzzle you’d like to complete and clicking on a puzzle piece that you do not already have. You will then be prompted to battle. If you win the battle you will gain the desired piece.
Completing puzzles is very useful, you will gain new girls as rewards.






How do I restore energy, attack and defense?

Time will restore energy, attack and defense points. Leveling up will also top these up.




How do I receive gifts?

You can find your gifts in the drop down menu under “Gift Box”, press “Select All” and then “Get”, the girts will go to their appropriate section.




Xanduras posted a very in-depth and helpful comment, we've attached it here as it is so informative, it may help players out if they have questions.



Best Stats to boost:
- Attack and Energy (Defense not worth boosting because the people who attack are those who are confident they can win. Also, defense wins only provide Eros, whereas Attacking give Eros, Puzzle Pieces, and Affection).
- Also, I'm finding that a lot of the players who boost defense tend to keep lots of Eros on hand. Which means high rewards for beating them


Training
1. Training cost in Eros = level of unit *100 per card used.
So training with 10 cards at level 1 costs 1000 gold.
Training with 10 cards at level 20 costs (lvl 20* 100 per card) * 10 cards = 20000 eros


2. I trained up a common 2-cost card to C+ with max affection and max level on both feeder cards, and then maxed out the C+ card.
C card (tsubomi): 276 / 206
C+ Lvl 20(max) card: 1597 / 1123 (800 att per point!)
For comparison purposes, I have a level 44/60 SR card that costs 14 points, and is 5454 / 5454. That's only 389.6 attack per point.


I should of recorded (but forgot):
- Base card level 10 stats.
- Upgraded card base stats.


Card Skills
Skills:
- The same card can have different skills.
I have 2 SR Hana Harunas with the same photo. One has Passionate Serenade (Def Str Up), one has Energy Vacuum (Att and Def of allies with same attribute Up).
You need the att/def stats to match the skill (e.g don't level up a high attack, low defense card that has Passionate Serenade)!
- It looks like R and above can have skills, with the skills getting better the rarer the card.


Combat System
- If your attack total is higher than the enemy defense total, you win. Otherwise you lose.
- The rewards are Eros, based on how much the player has (so try to minimize the Eros you're holding!).
- Stat bonuses are provided by: being the same card type as your leader, cards having skills, and cards having the same tag as each other.
- Winning an attack earns all the cards in your attack deck 5 Affection


1. Attacking will use up all points you have. It will bring the highest attack or defense card per point card possible.


Leftover points are used to bring additional cards to the battlefield, which function at 80% of its stats * points available / cost of card
So if I had an 1600 attack, 2 cost card and had 1 additional point. It would function at 1600*80%* 1pt/2pt cost = 640 attack.
If I had 3 points. It would function at 1600*80%*2pt/2pt cost = 1280 attack, and another card will be brought.


Note: the additional card tags are not counted for bonuses.


2. Defensive strength = total points you can bring with you into battle. You can load up your defensive army with 5 SR/UR/Legendaries, but that doesn't mean they will all appear.
Best players to attack: users who load up their armies with UR/SR/R cards, where the leader and the other cards don't match (having same type as leader gives bonus att). It's easy wins!


Gacha
- The Free Gacha via Gacha points or Bronze Tickets has gotten me anything from Common cards to Legendary. It provides cards of all types.
- The "Grab a (card type)" tickets seems to have cards not offered in the Free Gacha (or maybe the Free Gacha has so many that these ones haven't shown up).


Assignments
1. The "Three cheers..." assignments have set rewards.


2. The other assignments seem to have randomized rewards, where:
- there are 3 choices
- what you get of those 3 choices is random.
For example, Nouveau riche IT company seems to have the choices of:
500 Eros, 800 GachaPt, (200 or 300) GachaPt.
So you may only get 500 Eros, or 1 of each, or even 2x 800 GachaPt + other rewards (have had it happen).


3. The Expert Assignments (I have 3, 2 of which I can do with 100% success rate) require cards at level 30, and 1 requires cards at level 40 to complete.
I haven't done them because they take 12 hours and 24 hours respectively, and taking a high-level card out of action for that long is painful.
I'll probably do the 12 hour one tonight before I go to sleep though, and see what it gives tomorrow morning
But overall, leveling common and uncommon cards isn't worthwhile for assignments (except for use as 80% combat cards).


Affection Requirements to max cards:
Common: 20
Common+: 100
Uncommon: 30
Uncommon+: 150
Rare: 40
Rare+: ?
SR: 50
SR+: ?
UR: 60
UR+: ?
Legendary: 70
Legendary+: ?


Card Max Levels:
Common: 10
Common+: 20
Uncommon: 10
Uncommon+: 20
Rare: 40
Rare+: 50
SR: 60
SR+: 70
UR: 70
UR+: 80
Legendary: 90
Legendary+: 100
Ultimate: ?
Ultimate+: 120