It is crucial to avoid "free activation key generators" or pirated downloads. These sites often distribute malware, spyware, or ransomware, and the keys generated are generally invalid or blocked by Steam. Always use official or reputable third-party resellers to protect your computer.
You might be looking for an external activation key because the game has vanished from mainstream platforms. This is a common issue with movie-tied video games due to licensing agreements.
Once validated, the game will appear in your Library, where you can download and launch it. Game Overview: Battle Los Angeles Genre: First-Person Shooter (FPS) Developer: Saber Interactive Publisher: Konami Platforms: PC (Steam), PS3, Xbox 360 Storyline and Gameplay