It is widely installed in many online games to block possibly malicious applications and prevent common methods of cheating.

[5] GameGuard hides the game application process, monitors the entire memory range, terminates applications defined by the game vendor and INCA Internet to be cheats (QIP for example[citation needed]), blocks certain calls to Direct X functions and Windows APIs, keylogs keyboard input[citation needed], and auto-updates itself to change as new possible threats surface.

Since GameGuard monitors any changes in the computer's memory, it will cause performance issues when the protected game loads multiple or large resources all at once.

[7] Additionally, some versions of GameGuard had an unpatched privilege escalation bug, allowing any program to issue commands as if they were running under an Administrator account.

Some editions of GameGuard are now bundled with INCA Internet's Tachyon anti-virus/anti-spyware library, and others with nProtect Key Crypt, an anti-key-logger software that protects the keyboard input information.