Walk through the hole to find a hidden rail control room. Inside, you will find the Railgun Sniper (one-hit kill until Act 4) and a console. Interact with the console (press E, Up, Down, Left, Right quickly). If done right, the screen flashes green, and a train will drive through the main tunnel outside, killing every zombie on screen instantly.
For players looking for a different kind of "secret," the developer included several cheat codes to instantly unlock superior firepower: : Unlocks every weapon in the game. stamm0 : Gives ammo. stexp : Adds experience for a new level. stgod : Makes all skills 100/200, adds 50,000 money. zombie shooter 2 secret locations better
In the very first few levels, look for walls with cracks or slightly different textures. In the subway and factory environments, many walls can be destroyed by rocket launchers or simply intense gunfire. Walk through the hole to find a hidden rail control room