All weapon types are available to buy at the level hubs and, taking into account inventory weight limitations, can be mixed and matched to progress several perks at once. Each levelled tier offers a choice of two boosts, so it's tempting to focus on a particular class to unlock its strengths, but how you decide to do that is enjoyably freeform.
Using the weaponry of that perk, or performing certain actions tied to it, will level it up. Each perk represents a class, with specific starter weapons and gear. Where the game varies things up is with its perks: a class-based progression system that's as open-ended as it is surprisingly deep. After each round, any money earned can be spent at one of a number of hubs scattered across the level here ammo, armour, and weapons can be bought or sold before the next wave. Players attempt to survive ten waves of randomly spawning enemies of various types. Anyone who's ever played a co-op FPS before will be familiar with the basic flow of Killing Floor.
