Nexon and Marvel Games' digital card battle game, Marvel Battle Lines is a pretty simple game with one very unique mechanic. You're basically playing Marvel tic-tac-toe but with a slightly revamped grid. Except, none of your tic-tac-toe strategies will work here.
That extra row, however, massively changes your strategy. And because players have HP, you can take a "line" attack to the face and still win the match, which is definitely not an option in tic-tac-toe. And while cards all have different attack and defend stats, plus summon costs, Battle Lines has more in common with Magic: The Gathering than you might think. Add the magic cards, which can absolutely KO any opponent's card off the board or heal your own cards, the game is pretty deep in terms of player strats.
Its might actually be the deepest Marvel CCG we've seen in a long time.
Players have a ton of options for play, from the single-player campaign with an original story by Alex Irvine, to PVP, to specific challenge decks, to weekly and monthly events, to a social guild system. There's basically something for everyone. Granted, the story isn't the most sophisticated, but the simplicity actually works well. Being a mobile title, players may take a long time between stages.
Cards can be levelled up if you have enough duplicates of the card. While that will increase the card's attack and defense stats, it doesn't give a massive boost and does not effect summon cost or rarity.
There is of course a microtransaction system. You can buy card packs with real money, or use the earned currency. Players earn both soft and hard currency, which levels the playing field a bit for free players. The daily card packs also help.
Honestly, the only gripe I have with this game is how frequently its updated (sometimes twice in a week), and how often the UI breaks. The app rarely fully crashes on me, but I often get stuck in the card library with no way to return to the game putside of shutting the app down.
Overall, however, Battle Lines is a solid mobile game and it'll scratch your Marvel CCG itch quite nicely.