You might be surprised to learn that the nastiest thing about BitMonster's zombie shooter Gunner Z isn't the zombies. Having apparently poured all of their warmth and creativity into last year's charming RPG adventure Lili, the ex-Epic staffers decided to muddy up the App Store waters with yet another undead-themed blaster.

However, in their quest for the mighty dollar, the team has concocted a freemium framework which does its level best to impede your progress and hamper your enjoyment, in the hope that you'll throw down some cash out of sheer frustration.

You take control of a a gun turret which is mounted on the back of a humvee. The aim of the game is to clear the streets of zombies, enemy vehicles (zombies can drive now?), flying drones, and any other hostiles you come across.

The shooting controls are serviceable - you fire and switch weapons with the left thumb, and aim with the right. At the beginning of the game, your cannon is plagued with recoil, lengthy reload times, and limited ammo capacity. As you complete missions, you are invited to upgrade your armour and weaponry.

However, it's not good enough just to purchase upgrades and get to work. Yep, you guessed it: there are wait timers to contend with. As we've come to expect from this riff on the free-to-play model, there's a second currency which can be used to speed up repairs. And, as we've also come to expect from these situations, this currency runs out pretty quickly.

The game's solution is to recommend you keep two vehicles on the go, allowing you use one while the other is undergoing upgrades or repairs. Rather than speed up your rate of progress, though, it actually halves it, effectively forcing you to buy upgrades twice. Of course, there's always the option to buy currency with real cash. However, with no option to unlock the game and wait timers pervasive throughout, you're simply flicking pennies into a bottomless well.

Without the aggressive freemium baggage, Gunner Z would simply be a decent-looking run-of-the-mill zombie shooter. As it is, it's another showcase for the dangers of placing greed over good game design. Avoid.