Marvel Battle Lines sounds like the kind of mobile game that could easily hook millions of people. Mixing one of the hottest licenses in the world with a genre in card battling and collecting that frequently feeds addictive impulse should have been a slam dunk. Instead, Marvel Battle Lines is a mediocre time-killer that begins promising before descending into the kind of microtransactional model that feels exploitative.

Marvel Battle Lines begins with a simple premise - you're a civilian who has accidentally become infused with a shard of the Cosmic Cube, which gives you the power to see people as trading cards and do battle on a playing field Iron Man came up with to help you visualize your newfound abilities. It's messy, and developer NEXON didn't try particularly hard to explain why the protagonist is slinging cards alongside some of the universe's strongest fighters, but it's forgivable since the rest of the story is just a mashup of greatest hits in the Marvel universe. Everyone shows up, from Cottonmouth to Hela, and even if it's a jumbled mess it's at least an entertaining one. Localization issues aside - Nick Fury screams "DAMM IT" in a particularly funny attribution - the game uses its Marvel licensing well when it comes to narrative.

Related: Which Marvel Characters Should Get Their Own Games Next?

Gameplay also starts out promising. Marvel Battle Lines is kind of a mix between tic-tac-toe and a traditional TCG, with players looking to line up their cards in particular formations (diagonal, three-across, X-shaped, etc.) to damage the enemy leader. That's complicated by the fact that cards have abilities that interact with other cards, sometimes destroying them outright, other times affecting the playing field so that what looked like the perfect time to strike has now been blocked. There's a lot of tactical promise shown in these designs and the early gameplay in Marvel Battle Lines threatens to create the exact kind of positive feedback loop that has made other games so potent in the mobile market.

Then the enemies start getting progressively more powerful cards, and it all goes downhill rather quickly. Marvel Battle Lines has one of the more unforgiving microtransaction models in recent memory, offering three free cards a day and a gold/premium gem system that severely punishes players looking to play for free. There's no time-restricting energy system to speak of, so players can dive into the game's modes as much as they like, but that doesn't help when opponents begin to play cards that just outclass the ones players are given from the beginning.

Marvel Battle Lines is Way Too Unbalanced

In short, the balancing in Marvel Battle Lines is abysmal. Rarer cards are so much more powerful than common ones that the power curve becomes absurd quickly. While smart gameplay management and lucky draws can usually win after repeated efforts, it gets grind-y way too quickly. Within a few hours the game feels like a slog to the next goal, and cards opponents play that look fun are distant dreams on the horizon as players drift through a see of mediocre cards with ineffective or no abilities to speak of. While launch day quests have been relatively generous, the store system itself is not, which indicates potentially poor long-term health for the game's card acquisition model.

Again, this wouldn't be a huge issue if the game didn't try so hard to exploit its players, but it does. The prices in the store are silly, and it takes a ton of grinding just to get a basic card pack, which doesn't even guarantee particularly good results. Having to play the same cards over and over to start the game makes it start to drag, and the in-game rewards for completing campaign missions don't spice things up enough to prevent burnout. Once players are able to acquire better cards, the game picks up a little, but for all the variety involved in including so many different characters, the games play out extremely similarly.

Player versus player is also part of the Marvel Battle Lines experience, although unlike the rest of the game, it's fairly reasonable. It never felt like the pairings were unfair, and the ranking system keeps card strength in order. PvP is enjoyable and definitely the most interesting part of Marvel Battle Lines, and if nothing else, should be a reason to check it out initially.

Marvel Battle Lines feels like it has been designed explicitly to cash in on the Marvel license without offering much in return. The thinly-veiled attempt at creating a collectible card game that features all the heroes and villains of the Marvel universe quickly unravels to reveal a shallow game that wants players to cough up cash to progress. Maybe it's the kind of time-killer a diehard Marvel fan would be willing to suffer through, but ultimately, Marvel Battle Lines falls well short of the standards that mobile games like Pokemon GO, Fire Emblem Heroes, and Star Ocean Anamnesis have set in recent years. Unless you really want to stick it to Thanos, avoid the imbalance at play in Marvel Battle Lines.

More: Marvel Doesn't Know What To Do With Namor in Comics, Either

Marvel Battle Lines is out now for iOS and Android. We played the Android version for review.