If you have never heard about the game before you can look at the Gods Unchained Beta Gameplay trailer here:

Why use the Blockchain?

Gods Unchained is using the Ethereum Blockchain to bring true ownership to the cards, making them fully trade- and sellable on any market featuring ERC-721 tokens. Essentially making the game a Collectible Card Game. The cards will be trade- and sellable after a short balancing period, the developers use to make sure cards will not be too overpowered.

The team is using a smart contract for the card-pack distribution, making the probabilty of Common, Rare, Epic, Legendary and Mythic cards provably fair. Also the shine of the cards: Plain, Shadow, Gold and Diamond is calculated using this smart contract. Shine has no actual effect on gameplay, it just introduces rarity and cool animations and effects when the cards is played.

There is an arcticle by Hackernoon, who examined the smart contract that handles the Gods Unchained Card Pack purchases, below if you are interrested.

The team also used a smart contract for auctioning the first Mythic card released which was sold for 146.279 ETH. You can check out the auction page here. There are 2 Mythic cards remaining, of which only one will be in existence at all times. The probability to draw a Mythic card is one in a million and there are a maximum of 4 unique Mythic cards created each year.

Gameplay Mechanics

Gods Unchained may look and play a lot like Hearthstone, but this is not a bad thing in my opinion. This is actually a great entry point if you have played or watched Hearthstone before. All in all it should not be too complicated if you have never played any card games before. The mana, attack and health system and the basics game mechanics can be understood really fast.

There are definitly differences in gameplay mechanics though when you compare Gods Unchained with Hearthstone. This could make the game compelling for people who are currently invested in Hearthstone too.

Let us take a look at two major game mechanics which are different:

Mana Progression

God Powers/Ultimates

Mana Progression

The team decided to introduce non-linear Mana-Progression to open up the range mid game decks can operate in and to make the late game feel like it really is LATE game. Controlling the pace of the game like this also opens up the possibility to make late game cards more powerful. If your deck is built around the lategame you need to survive way more turns then in Hearthstone before you can thrive on your powerful high mana cards. The Mana-Lock System is working like this at the moment of the closed beta:

Mana Gems 1–5 unlock after 1 turn each. Mana Gems 6–7 unlock after 2 turns each. Mana Gem 8 unlocks after 3 turns. Mana Gem 9 unlocks after 4 turns.

If you want to read more on the Mana System and other game balance related topics here is an article by their Lead Balance Designer ADWCTA on the Mana System:

God Ultimates

In Gods Unchained your Gods have Powers you can chose from at the beginning of each game. Every God has 4 Basic abilities and 1 Ultimate Ability. There is one subtle difference between ultimates and basic abilities. Basic abilities are weaker but can be used every turn as long as you have enough mana. If you chose your Ultimate ability you can use it only once per game as long as you have enough mana, enabling the ultimates to be way stronger in return.

Here are some Links to the Gods that will be featured in Gods Unchained at launch, if you want to check out their lore and abilities.