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How to play:

Energy:

In short, there are 3 different types of energy: Palm, eye, and solid. These energies will be used to play various cards. Your energies can be viewed in the bottom left corner when in-game. If you need more energy, the fastest way to get it is by playing energy cards.

They typically look similar to this:

Notice the type of energy and amount of energy you will gain shown at the bottom of the card. This is the biggest indicator of an energy card.

However, if you do not have any energy cards in your hand, and you need more energy, you may skip your turn. This will grant you 1 energy of each type.

Play a card:

If you have the required energy, you can play other cards too. 

To know how much energy you need, you can hover on a card, and a tooltip will appear.

The energy needed to play this card is displayed at the bottom of the tooltip. You may have also noticed that the tooltip will also show the card's description and price in dollars ($). This card in particular is called an entity card. It has attack and defense values shown at the bottom of the card itself. When played, it moves to the battlefield, where it can attack and block incoming attacks.

There is another type of card that can be played, which is the action card.

These cards have nothing at the bottom of them, unlike the energy and entity cards. This is because action cards can have completely different effects from one another. To know what a certain action card does, you'll have to check its description by hovering your mouse on it. A neat perk of playing action cards is that they don't use your turn! You can play as many action cards as you want in a single turn, but if you do anything else, your turn is over.

Attacking and blocking:

If you've played an entity card, it's probably time to start attacking with it.

To attack with a played entity card, on your turn, click it! If your opponent has any entity cards played, then they will block with one to reduce or mitigate damage done to themselves.

The entity battlefield is above your hand cards.

If your enemy chooses to attack you, a distinct sound will play, along with a message in the center of the screen. You will be able to see which card is attacking as text will appear above that card. If you have any entity cards, you will have to click which one you want to block the attack. If you do not have any, the damage will go straight to your health.

Which entity wins when attacking though? It's simple. 

If the attacker's damage is higher than the defender's defense, then the defender will return to the deck, and some damage will go to whoever played the defender.

If the attacker's damage is the same as the defender's defense, then the defender will return to the deck. No damage will be applied elsewhere.

If the attacker's damage is less than the defender's defense, then the defender successfully blocked all damage, and nothing will happen.

It is also worth noting that after an entity attacks, they will become tired. In this state, they cannot attack or block. To know if your entity is tired, check if the card has its signature white border. If it doesn't, your entity is tired.

Outro:

I would like to leave some of the other mechanics for the player to discover, but I explained all of the complicated things (I think). If you do have any questions, please feel free to leave a comment, I'll respond as quickly as I can.

The game in its current state is unfinished, there were things that I would've liked to have added, but there wasn't enough time. For example, right now, the game will endlessly go on until the player runs out of health in a battle. I wanted to make a proper win condition, and I'll definitely have to do that later.

Anyway, I hope you will enjoy this game, even if this is a very early version of it.