Boxhead: More Rooms

Even more rooms! This addition to the Boxhead series features not only 8 new rooms to kill or be killed in, but also tons of new features. There are a lot of new weapons and upgrades for you to earn if you can combo-kill the zombies fast enough, a life meter, so you can take several hits instead of dying immediately with one hit, and multiple difficulty levels that the player can select. Try playing on Nightmare mode for the ultimate challenge!

Another very noticeable new feature is the addition of a new enemy type: the devils! These guys are tough! Not only can they take a lot more damage than the standard zombies, but they shoot fireballs at you! The best strategy to take against the devils is to shoot them repeatedly as fast as you can. They'll be knocked back each time you hit them, and if you can keep hitting them fast enough they'll never have the chance to launch a fireball. Give them even a little time between shots and they'll light you up!

Source:

Official game site