Unofficial versions are prone to crashes and lack the latest performance fixes. Limited Gameplay:

If the game is a "portable" repack, there is no installer. You simply open the extracted folder and run the game executable directly.

While legacy versions are popular for nostalgia and modding, the most secure and feature-complete way to play Counter-Strike is through the official Steam client. Official versions receive the latest security patches and anti-cheat updates.

If you own CS:GO on Steam before it became CS2, you can use the -insecure launch option and sv_lan 1 to play offline without a crack. However, this still requires Steam to be running.