Lockdown: System of the Dead

In the wake of a sudden zombie apocalypse, the world descends into chaos. Amid the ruin, Jaden Knightley awakens a mysterious power—the Lock System. Every time he kills a zombie, he earns a Lock, each inscribed with a number. These Locks can be "opened" to gain random attribute boosts, skills, or rare items, making him stronger with each encounter. But not all Locks are simple… Some are cursed, others require keys, and the rarest ones can alter reality itself.