Valkyrie Crusade (jp.:神界のヴァルキリー) is described as a mini-garden and TCG.
The main goal of the game is to collect and evolve different kind of cards which you use to either fight against other players or go into the campaign mode to conquer different areas and fight against potential archwitches.
Another feature of the game is, that you are able to build your own city inside your kingdom. You can upgrade important and useful facilities by spending resources on it. Building/Upgrading any facilities takes time. In fact, it is real-time based thus making every minute passing in real life, counts as a minute in game as well.
The very first thing a player will do if they enter the world of Valkyrie Crusade is to build their first buildings.There are a lot of either useful ones, or ones that are limited decorations and can be only obtained by via jewels or clearing a special event world.
Like I explained in the intro, you are also able to upgrade your facilities, like your castle or resource generating ones and many more. With each level your building is gaining, their upgrade prices and upgrade time increases as well.
Another objective in Valkyrie Crusade is conquering different areas.
The standard world "World of the Gods" is available all the time in Valkyrie Crusade.
Conquering areas lets you progress into the game further and also awards you with items after each completed area.
You complete an area by simply conquering all previous areas and the last one (usually marked as an Castle).
Each area has it's own set of unique "War Trophies". They can be obtained by processing through any area. The rate of getting one is randomized, but can be increased by certain facilities like the "Goddess Statue". Special War Trophies are "Sacred Treasures" which can be only found in certain areas. Completing one kind of a sacred treasure allows you to unlock different R Cards , most common pattern of the rewards are the first type of an R card as your first reward, a Metal Slime as your second reward, and as your third reward you'll get a second type of your first R card you've received from the sacred treasure.
Throughout your journey, progressing further into the game makes the enemies more difficult. Also, you'll use more vitality to make progress, and your progress bar also fills up more and more slowly.
Last but not least but the most important aspect of Valkyrie Crusade is the battle against archwitches. You encounter them randomly but the chance of encountering one can be further increased by special facilities like the "Magic School". An in-depth article about archiwitches can be found here.
In Valkyrie Crusade, you can also battle against players all around the world for sacred treasures.
You do not lose a treasure if you fight for one and lose, and for each battle, won or lost, you have to wait for a specific time to be able to battle for treasures again!
Note: Fighting against other players let you lose the amount of soldiers and doesn't reset the casualties unlike in archwitch battles!
The most important base of Valkyrie Crusade are the Cards.
There are over 300 unique cards that can be obtained by various summoning method, ranging from the lowest rank (N) to the highest (HSR).
To obtain (N) to (R) ranked cards, you can do a normal summon, those consume 100 friendship points per card. Up to 10 cards can be summoned at once.
A more detailed article about summoning can be found here.
Very last but not least, is the Harem system of Valkyrie Crusade what makes the game unique.
More than 300 individual cards have their own way to express and display their (deep) feelings towards their master.
Raising the intimacy level of a card to 30 leads into an event where the card usually confesses to the player. The card also gets a 5% bonus to its attack and defense stats.
The intimacy level can be raised randomly on any card that you have in stash by 1 level, by just logging into Valkyrie Crusade each day. It also can be mainly leveled up by just having the card in your team when taking part in (not necessarily winning!) battles.
Tip: Defeating bosses appears to increase the chances of intimacy levels going up, so repeating Campaign 1-1 for 8 vitality each run is a good place to work on maxing intimacy.