With titles like Zombieville USA exploiting the formula of 'zombies + shoot things + lots of weapons = good', this particular evolution of the side-scrolling beat'em-up started to crop up slowly, but surely across the App Store. Biofrenzy HD dips in to the same ideas-bucket and tries to tack on some much needed changes, streamlining the gameplay even further, however it still fails to address the key issue with games of this type - mindless repetition.

The controls are standard for games of this type, with players being given a basic set of buttons to move left and right, fire their weapon and a few special abilities to help turn the tide. Players can only take a limited amount of weapons in to each level, however instead of ammunition the weapons generate 'heat', acting as a natural limiter and giving players a good reason to switch between the arsenal they currently have available. Drops from the zombies will occasionally provide benefits like health/skill energy and heat reduction, but of note is the 'box of junk' that allows players to nullify zombies by throwing random objects on the heads of the zombies around them. This can provide a critical edge when low on health and trying to avoid that last deadly chomp, but it's also immensely cute too, invoking memories of Plants vs. Zombies and similar lighthearted games.

Biofrenzy HD shines on the visual front too, with detailed cartoonish designs that are crisp to look at and animated smoothly, adding splashes of blood without being over the top. Unfortunately the variety tends to thin out after the first few levels and while different areas provide some change the zombies remain almost unchanged late in to the game and players are reliant on their weapons to change things up.

The ideas in place for Biofrenzy HD are welcomed openly and the natural level of variety brought about by the heat system helps a lot, but unless you're really really really in to mass slaughter of zombies you get more eye candy than substance as far as gameplay goes. A decent release for hardcore fans of the genre, but less appealing to those who have been-there, done-that.