Zombie Break-in is a flash take on the COD zombies that fps gamers have known to love. Stop zombies from breaking in on an endless zombie rampage with 18 different guns to choose from and many different power-ups and upgrades. Kill the zombies, buy guns off the wall, collect power-ups, unlock rooms and buy upgrades. WASD – Movement. SPACE – Melee / buy. Mouse – Aim. Left click – Shoot. Shift – Sprint (hold down). G – Throw grenade (hold down to cook). E – Switch weapon. R – Reload.