I’m not enjoying the iOS version of Injustice: Gods Among Us, yet I can’t stop playing it. The reason I’m draining my iPhone’s battery by rapidly tapping its screen? Some of the content unlocked in the iOS game transfers over to the console versions, which release on April 16.

The iOS iteration showcases NetherRealm’s detailed character models, environments, and animations, but doesn’t pack much of a punch in combat. It’s more of a button-mashing affair; screen taps execute light attacks, and swipes unleash heavy attacks. Pressing two fingers on the screen performs a block. Depending on the character you are using, the light attack could be a punch, kick, or weapon strike. The same goes for the heavy assaults. You don’t have control over the individual limbs of the character, nor can you tell him or her to jump or even move. The basics of combat are just tap, swipe, or block.

For all of the characters on my roster, tapping out a combo using three light attacks prompts a fourth hit using a random directional swipe. If performed correctly, this strike always knocks the opponent down. Successful combos and blocks fill up a special meter that unlocks super moves. These moves freeze the game momentarily and give the player a five- to six-second window to rapidly tap or swipe the screen to enhance the power of the attack. If you hold out and fill up the entire special meter, an ultimate attack becomes available. Flash’s ultimate attack is quite amusing. He takes off in a sprint, and the camera pans out to show him running all the way around the world to build up the most devastating punch he can muster.

Most of the fights pit three player-selected characters against three CPU opponents, although most of the boss fights are against one suped-up hero or villain. The first eight battles are cakewalks. Just tap the screen any way you see fit and use your super powers when they become available and you won’t have any problem beating the snot out of every costumed character you face. While lacking in combat complexity, I got a big kick out of making Green Lantern, Nightwing, and other well-known DC faces look like fragile chumps.

That feeling of being all-powerful doesn’t last long, however. In the second tier of fights, the devastating combos I was landing somehow became ineffective. These combatants are much stronger and have double or triple the hit points of the characters I was facing before. To be able to beat them, I needed to level up my characters by grinding experience in the first eight fights. Leveling up characters brings bumps in hit points and damage dealt. Remember those ultimate attacks I was talking about? You can't access them until a character reaches level 20.

Completing battles for the first time rewards the player with random collectible cards. Some of the cards offer character-specific upgrades, such as Batman’s Explosive Batarang card, which grants him twin Batarang strikes with the chance to stun. Other cards lend support. Power Girl’s card provides +2-percent energy regeneration for all characters. The Yellow Power Ring card gives Sinestro a +10 damage bump.

If you don’t want to grind experience all day, you can purchase booster packs of cards or super move upgrades to better your odds. You can use in-game coins to buy these packs. After eight battles, I generated enough funds to purchase three bronze-level packs. I’d have to spend hours battling foes just to earn enough coins to purchase one gold pack.

On top of the constant need to unlock new powers and level up characters, players have to keep an eye on the energy of each character thrown into combat. Energy regains over time, or crystals can be exchanged to bring a character’s energy back up to full.

You know where I’m going with this. If you don’t have enough coins to purchase cards or crystals, you can open up your wallet and use real cash to fund your spending expedition. And if you go in this direction, be prepared to spend a lot. Card packs, crystals, and additional characters are surprisingly expensive.

Superman will set you back around $20. The same goes for Batman and Doomsday. These characters are not instant game changers, either. When new characters are added to your roster, they all start at level 1. You have level them up, otherwise they go down in just a few hits.

The only reason why I’m tapping this damn screen is for the hope of unlocking skins for characters when the other Injustice releases on April 16. The Batman Beyond skin, for example, is one of the highly coveted items. From what I'm told, I can only get this skin by unlocking Batman. I need over 100,000 gold coins to get him. That's a hell of a lot of uneventful tapping.

Injustice is available now in Apple's App Store for free.