Its a videogame. Play it.
Nerd.
Fine...effort. Imagine a very well made trading card game mixed with unit battles ala FFT or Xcom (on a 2d plane). With gorgeous pixel art with intricate fight and spell animation.
With a tutorial and a single player challenge mode that actually teaches you the various mechanics each card/unit has.
With near instant matchmaking (because I guess a ton of people are playing?).
With one of the best UIs in the genre where you can see what each card/unit does by simply mousing over it. And not just what the card does per se, but for example this card has "growth", which is not specific to said card but a overall mechanic? It will explain that too in simpel text when you mouse over it!
It feels like you are playing a mix of magic the gathering and a board game, the rules are so well explained and crafted that you can pull off a bunch of cool combos and situations with yoir decks, because the nature of the actual moving the units part.
Example: Earlier I lost a game because I was chasing the enemy general (generals are the "main" card you need to kill, basically your avatar) around the field and I just couldnt get to her because the player kept shitting out a bunch of small minions between myself and her (which is part of not only that general ability but that defk in general), and because this uses tiles like FFT for example, I physically couldn't get close enough, it left me like "that is actually pretty fucking smart and neat and damn son"
Also the f2p-ness of it seems fairly generous for the few hours I played. You can unlock all 6 factions by just playing one practice game against them. You unlock cards as you level up factions. You constantly earn gold everywhere and you can buy booster packs with said gold (or, I assume, use it for draft runs like Hearthstone, which is a mode I just unlocked earlier but couldnt see if it needed gold to run because they gave me a free ticket, but the fact that it has tickets to run implies you need to buy them). There are daily quests like hearthstone aswrll (in fact most of the game modes are straight out of hearthstone).
I am super impressed with it and as someone who has dabbled eith many card games, this is the first one that I not only played more than 1 hour, but that I can see myself playing regularly. Hell, I told a friend of mine that basically only plays hearthstone and wow and he was playing it even longer than I was (he is a huge magic the gathering player too so he knows his tcgs).
I rarely give these long winded recomendations because... well im lazy and I think people should play what they want and not what others tell them to, but having said that,go play Duelyst because I'm telling you to.
Its also only like 500 megs and you dont even need to create a seperate account, so points for not requiring effort.