Deck builder card game

Setup:

Separate all cards with zero cost to buy and no cost to buy symbol.

Cards with no cost to buy symbol are the players starting decks, five white cards, one red, green and blue card each(8 cards per player)

The 12 cards with zero cost are separated in 3 piles(red/green, red/blue, green/blue). These cards make up one part of the market. Shuffle all other cards then draw and place 8 cards face up to complete the rest of the market.

Place the market and the common supply of energy cubes, 6 of each color(Red, Green, Blue and black) easy to reach by both players.

The non starting player gain 2 black energy on their first turn.

Start the game with 20 lives each. Win the game by lowering your opponents lives to 0.

The five stages of every turn:

1. You may take back energy on your cards to your supply.

2. Trigger cards with keywords (U:) Upkeep.

3. In any order:

One time per turn:

- Buy ONE card from the market by paying energy from your supply(any color), cards bought are placed in your discard pile.

As many times as you like:

- Discard cards to gain energy of that color to your supply(upper right corner) 

- Play cards by paying its cost in energy (upper left corner)

-Tap a creature to:

    Attack:

         Choose to attack a creature. Or attack an opponents lives, only if the opponent does not have 3 creatures.

    Or Produce:

         Produce energy (move energy from the common supply to your supply) and trigger any effect after this symbol ¬

4. Untap your creatures, non-black energy left in your supply may be stored on white creatures. Return all other energy to the common supply

5. Discard your hand and draw up to your hand size (default 4 cards)

General rules:

There are 3 card types:

Creatures, they got a red circle with attack power and thoughness.

Uppgrades, they got the text on top of the card.

Action , Text at the bottom and no red circle with attack power and thoughness.

You can have a maximum of 3 creatures in play. If more creatures are played, remove one of your creatures in play to your discard pile. If the replaced creature was tapped, the new creature enters play tapped.

If an energy of a specific color is gained, and there are no energy of that color left in the common supply, gain a black energy. If all black are missing, you gain nothing.

Cards that are not a creature or an upgrade,  are played directly in to your discard pile. upgrades are played on one of your creatures, attach the card underneath and slightly on top of the creature. A creature can have multiple upgrades attached.

Your destroyed creatures and upgrades attached to the creature, are placed in your discard pile. 

Bought cards from the market are placed in your discard pile. If you bought one of the uniqe 8 cards, draw and place a new card in the market.

When you need to draw cards and your draw pile are empty, shuffle your discard pile to make your new draw pile.

Your creatures do not take damage when attacking. An opponents creature are destroyed, when your combined power from all your attacks, on the same turn, equals or exceeds that creatures toughness.