So being a veteran of modern and older TCGs and seeing this was the only one such with positive reviews on Steam I would like to give it a try. Long review ahead.
Most people view reviews to see if the game is worth their time so I will give my opinion on that.
To begin, first and foremost about game optimization.
You are required to make an account on the game's platform, which can be done through the main menu quickly without need to confirm or verify or anything such. Aside that the game crashed once while I was playing it after 6 hours, but reconnect was instant and I didn't lose anything. It also crashed when I hit the quit button but it quitted normally in some seconds.
Noteworthy I really like the artwork of the game. Every card is basically a good quality gif of anything from primeval creatures to alien demon entities in a serious anime style(actually very close to Attack on Titan animation if you ask me) which I personally like.
Secondary and most important, if you have experience with other TCG games you will probably like this as it combines many interesting features and comes out as an innovative title. It may be weird, unbalanced, easy to lose track but these qualities apply to most leading TCGs currently(YGO/MTG etc) as long as you are not familiar with them.
To give some insight into the gameplay, without analyzing the strategies or the cards(yet):
You have a deck of 40 cards(by default) of creatures and abilities, the creatures have a mana cost, attack and defense values, and their own effects, while abilities sport their own mana cost for their effect. By default the mana progresses simply like hearthstone.
Disclaimer: I am pretty sure that it's not called mana in the game but just Resource but it is easier for me to type it and reference it this way.
So every player starts at 1 mana(resource-bah) and they get 1 per turn capping at 10 to play their cards with. The creatures funtcion like Hearthstone as well, as in their health does not regenerate after combat and any changes to their stats usually remain put if increased by an effect. Worth noting that killing a creature that boosts the health of others can result to the death of other creatures(as in MTG) something that does not happen in Hearthstone. So this seems pretty basic but the core gameplay is where it takes a twist.
Every player has 4 zones, the Support Zone, the Assault Zone, the Defense Zone and the Command Zone(if I get any name wrong plz don't flay me). When you "play" a creature it appears in your Support Zone, acts as if it has entered the battlefield and is subject to effects of your and enemy creatures(but not spells yet). It cannot swap zone at the same turn. On your turn you can indefinitely move creatures from your Support Zone to either the Defense or the Assault Zone(you can also indefinitely swap them). When you have done so and played any spells if any both players click ready and each player's Assault Zone tries to beat the other player's Defense Zone, in a fashion of the leftmost card attacks first.
You can change the row in which your creatures attack which is very important in the game. A tricky part is that abilities constantly update. If my 4/4 that gets +2/+2 when an enemy dies kills the enemy's attacking 2/2, its ability procs and it becomes a 6/4 evidently tanking an infinite amount of 2/2s. And such abilities exist in abundance in the game.
A versatile part is you can retreat everything you have back to the Support Zone again indefinitely. There is no limit to how you move stuff you have already summoned so if you suspect your enemy is about to bomb you you can massive retreat and such. Many cards heal/boost the ones adjacent to them every turn and keeping these in Support Zone is the ideal way to activate their effects.
The last and most interesting zone is the Command Zone. Kinda familiar with how commanders work in MtG, from your deck you pick 3 cards to put in your Command Zone. Any cards. They are not subject to targeting abilities but they are subject to area of effect spells(boosts or damages), their passive/active abilities can trigger and if you pay their cost you can instantly put them in your Assault or Defense Zone. The possibilities with that are endless.
The winning condition is, two winning conditions by default which has never been done in TCGs I have seen before. By that I mean that every player has 2 bars not one, Health and Morale. Health is the damage when you get attacks while undefended(or when enemies slip past your defenses) and Health is 100/100 when most creatures start with attacks between 4-8, however that does not make the games longer as pretty much anything ends up boosting itself. Morale is again a 100/100 bar. Every creature has a morale cost, which is how much morale you lose if the creature dies. If your Morale or Health drop to 0 or less, you are ded. Since combat happens at the same time for both players however it's very easy to do draws, with both players putting nothing on defense and going for the face.
The campaign(8 missions per each of the 8 game factions, makes sure you reach Level 7(You can play online after 4 and Ranked after 10), and it also makes sure you get the basic cards of every faction, try some premade decks while at it and get some extra packs of pre determined cards and 1 random booster per level.
Speaking about the campaign here is a faction overview:
-The Red Dawn Army(Red Colour) a lighter version of Warhammer's space marines that try to blitz their enemies out or boost their own stats for quick attacks.
-The Genesis Industries(Blue Colour) a faction utilising Droids that boost each other and Artifacts that have good active abilities while they stay in your Support or Command Zones.
-The Warpath(Green Colour) the big huge bulky high mana cost trampling creatures(nothing impressive but their art is very nice and cute).
-The Awakened of Avarrach(Yellow Colour) a horde of robot zombies that focuses on its creatures constantly dying which boosts everything else they have and/or killing enemy creatures with effects that transport them to your Support Zone rather than the enemy's graveyard.
-The Verore Cult(Purple Colour) your everyday evil wizard researchers that bomb the enemy creatures with spells while their own creatures grow stronger the more spells you cast sitting in their Support Zones.
-The Exiles(Pink Colour) literally a faction that references Warhammer again being what you would expect from Tzeentch's demons. They focus on Exile X keyword which means if you discard a card and then pay X something happens(usually that card coming back as a stronger demon tentacle abomination).
-The Dragon Descendants(Teal Colour) are a gimmicky monk like race with cool animations that remind the Avatar series that focus on defending and healing to destroy your enemy's Morale.
-The Overseers(White Colour) my favorite faction*reasons* that consist of anime-like busty angels with blazing halos and pistols outfitted in tight swimsuits(there are also some unsettling male cards) and well, just every single gif from this faction's collection is epic on its own specific way. Their specialty is death from above.
For those who just want to check this out, play the campaign and explore the innovation, I definitely recommend it. If you are experienced with TCGs you will like it or at least give it credit for being brave to do stuff like that, if you are not into TCGs I am sure you will find it confusing but the Tutorial is there and every card explains what its ability keyword means the first time you look at it. The story has some considerable plot as well!